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Author Title Year Journal/Proceedings PDF
Amouroux, N., Restagno, F. & Leger, L. Adhesion at Poly(Butylacrylate)�Poly(Dimethylsiloxane) Interfaces 2007 Journal of adhesion   article
Abstract: We present an investigation of the adhesion modulation mechanisms of silica-like

nanoparticles (MQ resins) incorporated in polydimethylsiloxane (PDMS) elastomers

and acrylic adhesives. The Johnson-Kendall-Roberts (JKR) test has been

used to gain information on the both zero velocity and the velocity dependence of

the adhesive strength, avoiding as much as possible contributions to the adhesive

strength of bulk dissipation in the adhesive (which is not the case with peel tests).

As the incorporation of the MQ resins into the elastomers deeply affects their own

mechanical properties, the loading and unloading curves of small poly(butylacrylate)

(PBA) lenses on either PDMS elastomers, adsorbed PDMS and pure MQ resin

layers are compared in a systematic manner. The PBA chains are observed to have

a neat affinity for the MQ resin nanoparticles. When MQ resins are present at the

interface, they tend to prevent facture propagation, thus producing a larger deformation

of the PBA lens. The modulation of adhesion is then dominated by the corresponding

dissipation inside the acrylic adhesive.

BibTeX:
@article{Amouroux2007,
author = {Amouroux, N. and Restagno, F. and Leger, L.},
title = {Adhesion at Poly(Butylacrylate)�Poly(Dimethylsiloxane) Interfaces},
journal = {Journal of adhesion},
year = {2007},
volume = {83},
pages = {741�760}
}
      
Guena, G., Poulard, C. & Cazabat, A. M. The dynamics of evaporating sessile droplets 2007 Colloid Journal   article
Abstract: Experiments on sessile drops evaporating in a normal atmosphere without an applied thermal gradient are reported and compared with an available theoretical model. The liquids used are alkanes; water; and, more recently, polydimethylsiloxane oligomers. The substrates are silicon wafers, completely wetted by the liquid. Experiments with hanging drops allow us first to discard any influence of convection in the gas phase on the drop dynamics. The model assumes the process to be controlled by the stationary diffusion of the evaporating molecules in the gas phase. For alkanes and water, and in a limited range of drop sizes where gravity can be ignored, the model accounts very well for the dynamics of the drop radius, and rather well for the contact angle. This is no longer the case with the polydimethylsiloxane oligomers, where the very small contact angles require a more elaborated analysis of the drop edge.
BibTeX:
@article{Guena2007,
author = {Guena, G. and Poulard, C. and Cazabat, A. M.},
title = {The dynamics of evaporating sessile droplets},
journal = {Colloid Journal},
year = {2007},
volume = {69},
number = {1},
pages = {1--8}
}
      
Guena, G., Poulard, C. & Cazabat, A. M. Evaporating drops of alkane mixtures 2007 Colloids And Surfaces A-Physicochemical And Engineering Aspects   article
Abstract: Alkane mixtures are model systems where the influence of surface tension gradients during the spreading and the evaporation of wetting drops can be easily studied. The surface tension gradients are mainly induced by concentration gradients, mass diffusion being a stabilising process. A remarkable observation is that, at given initial volume, a drop of mixture often evaporates faster than one of the most volatile alkane. Depending on the relative concentration of the mixture, a rich pattern of behaviours is obtained, which is qualitatively the same for the three mixtures investigated (heptane-octane, hexane-octane and heptane-nonane). There is an intermediate range of concentration where a dry ring develops inside the drop. For lower concentrations of the most volatile alkane, it disappears completely before the end of the evaporating process. For larger concentrations, the drop is still a mixture till the end of its life. The coupling between evaporation, local concentration and drop shape will probably require a numerical treatment of the dynamic equations. (c) 2006 Elsevier B.V. All rights reserved.
BibTeX:
@article{Guena2007a,
author = {Guena, G. and Poulard, C. and Cazabat, A. M.},
title = {Evaporating drops of alkane mixtures},
journal = {Colloids And Surfaces A-Physicochemical And Engineering Aspects},
year = {2007},
volume = {298},
number = {1-2},
pages = {2--11}
}
      
Guena, G., Poulard, C. & Cazabat, A. M. The leading edge of evaporating droplets 2007 Journal Of Colloid And Interface Science   article
Abstract: New experiments on drops evaporating in normal atmosphere from smooth substrates in the situation of complete wetting are reported and compared with the available theoretical model. They are the continuation of previous work with alkane or water sessile drops, which is first briefly summarized. The model accounts very well for the dynamics of the drop radius, but the predictions are only qualitative for the contact angle, especially for small angles. Experiments with hanging drops allow us first to discard any influence of convection in the gas phase on the drops dynamics. Then the main part of the paper concerns new experiments with polydimethylsiloxane oligomers. These silicone oils are similar to alkanes as far as evaporation rate is concerned, but have lower surface tensions, and therefore smaller dynamic contact angles. The purity of the oils appears to be critical for the experiments, and requires a preliminary investigation. Then a systematic study of the drops dynamics is presented, as a basis for forthcoming theoretical work. (c) 2006 Elsevier Inc. All rights reserved.
BibTeX:
@article{Guena2007b,
author = {Guena, G. and Poulard, C. and Cazabat, A. M.},
title = {The leading edge of evaporating droplets},
journal = {Journal Of Colloid And Interface Science},
year = {2007},
volume = {312},
number = {1},
pages = {164--171}
}
      
Lamblet, E., Verneuil, E., Vilmin, T., Buguin, A., Silberzan, P. & Leger, L. Adhesion Enhancement through Micropatterning at Polydimethylsiloxane-Acrylic Adhesive Interfaces 2007 Langmuir   article
Abstract: Adhesion at polydimethylsiloxane (PDMS)-acrylic adhesive interfaces is shown to be enhanced through micropatterning of the PDMS substrate. By varying the geometry of the patterns (groves and hexagonal arrays of pillars of micrometer sizes, obtained through soft lithography techniques) and comparing rigid and deformable substrates, the respective roles of the geometry and the size and flexibility of the pattern features on the level of adhesion have been analyzed. For cylindrical pillars, two regimes are clearly identified: for a relatively low aspect ratio (h/r < 3, with h and r, respectively, the height and the radius of the pillars), soft patterned substrates are more efficient than rigid ones at increasing adhesion, pointing out the role of the elastic energy associated with the deformation of the pattern that is lost when the adhesive detaches from the substrate. Using scaling laws, the predominant contribution to that elastic energy can be further identified: deformation of the substrate underlying the pillars for h/r < 1.6 or bending of the pillars for h/r > 1.6.; for a high aspect ratio (h/r > 3), only rigid patterned substrates enhance adhesion, then the only possible contribution to energy dissipation comes from the enhanced viscoelastic losses associated with the pattern that induce modifications of the strain field within the adhesive layer. Soft, high aspect ratio patterns lose their efficiency even if still bent under the effect of the peel forces. This is because when bent, some of the pillars touch each other and remain stuck together, lying flat on the surface after the passage of the peel front. The bending elastic energy of the pillars (which is still lost) is then balanced by the corresponding gain in surface energy of the substrate in the peeled region. These systematic experiments demonstrate that the ability of the patterned surface to be deformed plays a crucial role in enhancing adhesion and allow us to propose a way to fine tune the level of adhesion at PDMS-acrylic adhesive interfaces, independently of the chemistry of the adhesive.
BibTeX:
@article{Lamblet2007,
author = {Lamblet, E. and Verneuil, E. and Vilmin, T. and Buguin, A. and Silberzan, P. and L�ger, L.},
title = {Adhesion Enhancement through Micropatterning at Polydimethylsiloxane-Acrylic Adhesive Interfaces},
journal = {Langmuir},
year = {2007},
volume = {23},
pages = {6966-6974}
}
      
Poulard, C. & Damman, P. Control of spreading and drying of a polymer solution from Marangoni flows 2007 Europhysics Letters   article
Abstract: We studied the drying process of polymer solution drops put on a wettable sub-

strate. Three stages can be identified. First, the droplet spreads until a maximum radius where

evaporation becomes dominant. The second phase is characterized by a constant radius due to

competition between spreading and evaporation of the solvent. Finally, the contact line recedes

until complete evaporation of the solvent. We show that, for complex fluids (highly viscous poly-

mer), the morphology is not determined by the evaporation process, the �coffee stain� effect but

essentially by the capillary instabilities. Using the appropriate couple of polymer/solvent, we

were able to obtain a outward, inward or a lack of Marangoni flow in the droplets, leading to the

formation of a rim, a drop or a uniform film, respectively.

BibTeX:
@article{Poulard2007,
author = {Poulard, C. and Damman, P.},
title = {Control of spreading and drying of a polymer solution from Marangoni flows},
journal = {Europhysics Letters},
year = {2007},
volume = {In press}
}
      
Amouroux, N. & Leger, L. Modulation of adhesion at acrylic adhesive-silicone elastomer interfaces 2006 Journal Of Adhesion   article
Abstract: We have recently reported a systematic investigation of the role of MQ resins (small silica-like nanoparticles) in the modulation of adhesion at silicone elastomer lens-nanometric thin acrylic surface anchored layer deposited on a silicon wafer through loading and unloading JKR experiments. This particular system was chosen as it allowed one to vary the MQ resin content in the elastomer, and to test its resulting effect on both the thermodynamic work of adhesion and the adhesive strength at elastomer-acrylic layer interfaces, avoiding any complication due to bulk mechanical properties of a relatively thick (in the micron range) acrylic layer. We present here a complementary investigation, aimed at understanding the role of the resins in the development of specific interactions at the interface. To do so the adhesive energy between silicone elastomers containing various amounts of MQ resins and model substrates made of self-assemble monolayers of thiol molecules with various amounts of carboxylic terminations have been measured through JKR tests. We show that the level adhesion at these interfaces results from a competition between increased interactions and decreased mobility associated with the incorporation of the resins inside the elastomer.
BibTeX:
@article{Amouroux2006,
author = {Amouroux, N. and Leger, L.},
title = {Modulation of adhesion at acrylic adhesive-silicone elastomer interfaces},
journal = {Journal Of Adhesion},
year = {2006},
volume = {82},
number = {9},
pages = {919--932}
}
      
Guena, G., Poulard, C., Voue, M., De Coninck, J. & Cazabat, A. M. Evaporation of sessile liquid droplets 2006 Colloids And Surfaces A-Physicochemical And Engineering Aspects   article
Abstract: The evaporation of sessile liquid droplets on a completely wetted substrate is a complex dynamical process. Available models assume that the evaporation flux is controlled by the stationary diffusion of the liquid molecules in the atmosphere, and that the interface is in equilibrium with the gas phasejust above it. This assumption must be reconsidered at the moving contact line, but the description of the thin edge of the drop is still an open question. The present paper reports experiments performed with alkanes on bare and grafted silicon wafers. It is shown that the short range part of the interaction plays no role on the dynamics, but provides an indirect evidence of the presence of a mesoscopic evaporating film left on the substrate ahead of the receding contact line. (c) 2006 Elsevier B.V. All rights reserved.
BibTeX:
@article{Guena2006,
author = {Guena, G. and Poulard, C. and Voue, M. and De Coninck, J. and Cazabat, A. M.},
title = {Evaporation of sessile liquid droplets},
journal = {Colloids And Surfaces A-Physicochemical And Engineering Aspects},
year = {2006},
volume = {291},
number = {1-3},
pages = {191--196}
}
      
Karbowiak, T., Hervet, H., Leger, L., Champion, D., Debeaufort, F. & Voilley, A. Effect of plasticizers (water and glycerol) on the diffusion of a small molecule in iota-carrageenan biopolymer films for edible coating application 2006 Biomacromolecules   article
Abstract: Translational diffusion of a fluorescein probe has been measured in iota-carrageenan edible films containing different amounts of glycerol ( 0, 15, 30, and 45%), using fluorescence recovery after photobleaching (FRAP) experiments. The effects of this plasticizer as well as the plasticizing effect of water on the diffusion of fluorescein have been studied in this edible coating mainly composed of natural biopolymer. Diffusion coefficients of about 10(-13) m(2) s(-1) have been measured in these films for water activity (aw) lower than 0.7. Above this water content threshold, fluorescein translational diffusion coefficient increases up to 10(-12) m(2) s(-1). Another interesting information obtained from FRAP experiments on this system is the ratio of the diffusing molecules which are immobilized in the carrageenan matrix at aw lower than 0.98. Moreover, films containing more than 30% glycerol (w/w carrageenan) present a huge increase of the diffusion coefficient of fluorescein at high water activity (about 2 orders of magnitude), this effect being less pronounced at low water activity. The increase of diffusion seems to be only related to the water content, and glycerol only acts through the enhancement of water adsorption. Therefore, in biopolymer films containing polyol plasticizers, the gain in mobility could be devoted to the effect of the ubiquitous plasticizing molecule, water, whose adsorption is increased by the plasticizer.
BibTeX:
@article{Karbowiak2006,
author = {Karbowiak, T. and Hervet, H. and Leger, L. and Champion, D. and Debeaufort, F. and Voilley, A.},
title = {Effect of plasticizers (water and glycerol) on the diffusion of a small molecule in iota-carrageenan biopolymer films for edible coating application},
journal = {Biomacromolecules},
year = {2006},
volume = {7},
number = {6},
pages = {2011--2019}
}
      
Leger, L., Hervet, H. & Bureau, L. Friction mechanisms at polymer-solid interfaces 2006 Comptes Rendus Chimie   article
Abstract: We present series of experiments conducted on model systems consisting of smooth solid surfaces covered with end grafted polymer chains at controlled surface density, and put into contact with either it polymer melt or it crosslinked elastomer of the same chemical species, and devoted to the characterization of friction as a function of the molecular parameters of the interface. Two techniques were used to do so: Near-Field Laser Velocimetry. which allows us to directly measure the local velocity at the interface when the melt is sheared against the grafted surface, and friction force measurements in it JKR like apparatus in the case of elastomers. Results will be discussed in the framework of molecular models of chain interdigitation and chain pull-out mechanisms.
BibTeX:
@article{Leger2006,
author = {Leger, L. and Hervet, H. and Bureau, L.},
title = {Friction mechanisms at polymer-solid interfaces},
journal = {Comptes Rendus Chimie},
year = {2006},
volume = {9},
number = {1},
pages = {80--89}
}
      
Poulard, C., Voue, M., De Coninck, J. & Cazabat, A. M. Spreading of nematic liquid crystals on hydrophobic substrates 2006 Colloids And Surfaces A-Physicochemical And Engineering Aspects   article
Abstract: The spontaneous spreading of nematic liquid crystals on hydrophobic silica substrates has been investigated at various scales by combining ellipsometry, profilometry and interferometry. While anchoring defects play a major role on hydrophilic substrates at the macroscopic scale, making the behaviour of films highly complex, they do not show up on these hydrophobic substrates. Then, the main specificity of the nematic films is the elastic energy associated to the long-range orientational order. Experiment shows that the macroscopic spreading laws differ from the ones of simple wetting liquids. Moreover, at the microscopic scale, a sharp transition between a mesoscopic, nematic film, and a molecularly thin precursor, is observed. The length of the precursor scales as the inverse of the macroscopic velocity, as expected for adiabatic wetting films. (c) 2005 Elsevier B.V. All rights reserved.
BibTeX:
@article{Poulard2006,
author = {Poulard, C. and Voue, M. and De Coninck, J. and Cazabat, A. M.},
title = {Spreading of nematic liquid crystals on hydrophobic substrates},
journal = {Colloids And Surfaces A-Physicochemical And Engineering Aspects},
year = {2006},
volume = {282},
pages = {240--246}
}
      
Schmatko, T., Hervet, H. & Leger, L. Effect of nanometric-scale roughness on slip at the wall of simple fluids 2006 Langmuir   article
Abstract: It is commonly acknowledged that roughness decreases the aptitude of simple liquids to exhibit flow with slip at solid interfaces. Most available studies have, however, been conducted on substrates for which both the surface chemistry and the roughness were varied simultaneously, making it difficult to identify their respective role on wall slip. To overcome this difficulty, we have developed a series of surfaces formed by grafting hyperbranched polymeric nanoparticles on a smooth, dense, self-assembled monolayer of SiH-terminated short poly(dimethylsiloxane) oligomers, allowing us to vary independently the surface density, the height, and the width of the grafted nanoparticles, and thereby the roughness parameters, while keeping similar surface chemistry. On such substrates, the boundary condition for the flow velocity of hexadecane has been characterized through near-field laser velocimetry. We demonstrate that decreasing the wavelength of the roughness at a fixed height strongly decreases slip, while increasing the height of the nanoparticles at a fixed aspect ratio of the roughness also dramatically affects slippage.
BibTeX:
@article{Schmatko2006,
author = {Schmatko, T. and Hervet, H. and Leger, L.},
title = {Effect of nanometric-scale roughness on slip at the wall of simple fluids},
journal = {Langmuir},
year = {2006},
volume = {22},
number = {16},
pages = {6843--6850}
}
      
Lamethe, J. F., Beauchene, P. & Leger, L. Polymer dynamics applied to PEEK matrix composite welding 2005 Aerospace Science And Technology   article
Abstract: Continuous composite processes such as thermoplastic automated tow placement are based on fusion bonding or healing of thermoplastic matrix. A good understanding of interdiffusion and crystallization, the main phenomena at the interface, is important. In order to investigate self-bonding in PEEK (Poly-ether-ether-ketone) and then in the same matrix reinforced by carbon fibers, a new experimental device has been developed allowing to prepare short-time welded samples which were then mechanically characterized using a wedge double cantilever beam test. The corresponding data on mode I critical strain energy release rate as function of processing conditions clearly show that both interdiffusion across the interface and crystallization are key parameters for the strengthening of the interface. Thermal modeling has also been developed and explains the importance of the interface cooling curve for healing. (c) 2005 Elsevier SAS. All rights reserved.
BibTeX:
@article{Lamethe2005,
author = {Lamethe, J. F. and Beauchene, P. and Leger, L.},
title = {Polymer dynamics applied to PEEK matrix composite welding},
journal = {Aerospace Science And Technology},
year = {2005},
volume = {9},
number = {3},
pages = {233--240}
}
      
Leger, L. & Amouroux, N. Modulation of adhesion at silicone elastomer-acrylic adhesive interface 2005 Journal Of Adhesion   article
Abstract: To characterize the role of small silica like nanoparticles (MQ resins) in the modulation of adhesion at polydimethyl siloxane (PDMS) elastomers-acrylic adhesive contacts, we have designed systems in which the roles of MQ resins in enhancing interactions at the interface and in increasing viscoelastic dissipations in the elastomer layer could be separated. First, the contact between elastomers with various MQ resin contents and PDMS layers made of densely grafted short chains has been investigated through Johnson-kendall-Roberts (JKR) tests, in order to characterize how the dissipations in the elastomer depend on the resin content. The same elastomers in contact with thin-surface-anchored acrylic layers were then tested through JKR tests to determine the role of enhanced interactions in the modulation of adhesion at the interface due to the resins. In these experiments, the thickness of the acrylic layer was kept small enough so that dissipations in the acrylic adhesive could be neglected. Both Go, the adhesive strength at zero fracture velocity, and G(V), the velocity-dependent fracture toughness, strongly depend on the MQ resin content and on the contact time, suggesting the progressive building of strong interactions between acrylic and elastomer chains.
BibTeX:
@article{Leger2005,
author = {Leger, L. and Amouroux, N.},
title = {Modulation of adhesion at silicone elastomer-acrylic adhesive interface},
journal = {Journal Of Adhesion},
year = {2005},
volume = {81},
number = {10-11},
pages = {1075--1099}
}
      
Poulard, C. & Cazabat, A. A. Spontaneous spreading of nematic liquid crystals 2005 Langmuir   article
Abstract: The spontaneous spreading of macroscopic drops of nematic liquid crystals on hydrophilic substrates has been investigated by interferometric techniques. There is a complex interplay between the elastic energy, due to antagonist anchoring at the interfaces, and the radial flow in the spreading drop. A relevant parameter appears to be the relative humidity of the atmosphere, because it controls the amount of water molecules adsorbed on the substrate and, therefore, the strength of anchoring defects. The spreading laws differ from the ones of simple wetting liquids, and contact line instabilities coupled to short- (anchoring) or large-scale (disclinations) defects of the nematic film are observed.
BibTeX:
@article{Poulard2005,
author = {Poulard, C. and Cazabat, A. A.},
title = {Spontaneous spreading of nematic liquid crystals},
journal = {Langmuir},
year = {2005},
volume = {21},
number = {14},
pages = {6270--6276}
}
      
Poulard, C., Guena, G. & Cazabat, A. M. Diffusion-driven evaporation of sessile drops 2005 Journal Of Physics-Condensed Matter   article
Abstract: The evaporation of wetting drops deposited on a substrate at thermal equilibrium under normal atmosphere is discussed. The evaporation rate appears to be controlled by the stationary diffusion of vapour molecules in the gas phase. Experiments with alkanes and water drops are fairly well accounted for by an isothermal model, taking into account the specific properties of thin films.
BibTeX:
@article{Poulard2005b,
author = {Poulard, C. and Guena, G. and Cazabat, A. M.},
title = {Diffusion-driven evaporation of sessile drops},
journal = {Journal Of Physics-Condensed Matter},
year = {2005},
volume = {17},
number = {49},
pages = {S4213--S4227}
}
      
Poulard, C., Guena, G., Cazabat, A. M., Boudaoud, A. & Ben Amar, M. Rescaling the dynamics of evaporating drops 2005 Langmuir   article
Abstract: The dynamics of evaporation of wetting droplets is investigated experimentally in an extended range of drop sizes to provide trends relevant for a theoretical analysis. A model is proposed, which generalizes Tanner's law in the presence of evaporation. A qualitative agreement is obtained, which represents a first step toward the solution of a very old, complex problem.
BibTeX:
@article{Poulard2005a,
author = {Poulard, C. and Guena, G. and Cazabat, A. M. and Boudaoud, A. and Ben Amar, M.},
title = {Rescaling the dynamics of evaporating drops},
journal = {Langmuir},
year = {2005},
volume = {21},
number = {18},
pages = {8226--8233}
}
      
Schmatko, T., Hervet, H. & Leger, L. Friction and slip at simple fluid-solid interfaces: The roles of the molecular shape and the solid-liquid interaction 2005 Physical Review Letters   article
Abstract: Using total internal reflection-fluorescence recovery after photobleaching, the local velocity, averaged over distances of 50 nm from the solid wall, has been measured for two different simple liquids, squalane and hexadecane, sheared on three smooth surfaces with similar roughness but with gradually decreasing fluid-solid interactions. We show that not only the strength of the fluid-solid interactions, but also the shape of the molecules of the fluid deeply affect the friction and the degree of slip at the wall.
BibTeX:
@article{Schmatko2005,
author = {Schmatko, T. and Hervet, H. and Leger, L.},
title = {Friction and slip at simple fluid-solid interfaces: The roles of the molecular shape and the solid-liquid interaction},
journal = {Physical Review Letters},
year = {2005},
volume = {94},
number = {24},
pages = {244501}
}
      
Bureau, L. & Leger, L. Sliding friction at a rubber/brush interface 2004 Langmuir   article
Abstract: We study the friction of a poly(dimethylsiloxane) (PDMS) rubber network sliding, at low velocity, on a substrate on which PDMS chains are end-tethered. We thus clearly evidence the contribution to friction of the pullout mechanism of chain ends that penetrate into the network. This interfacial dissipative process is systematically investigated by probing the velocity dependence of the friction stress and its variations with the grafting density and molecular weight of the tethered chains. This allows us to confirm semiquantitatively the picture of arm retraction relaxation of the grafted chains proposed in models of slippage at a network/brush interface.
BibTeX:
@article{Bureau2004,
author = {Bureau, L. and Leger, L.},
title = {Sliding friction at a rubber/brush interface},
journal = {Langmuir},
year = {2004},
volume = {20},
number = {11},
pages = {4523--4529}
}
      
Colin, C., Pasquier, C. R., Auban-Senzier, P., Restagno, F., Baudron, S., Batail, P. & Fraxedas, J. Transport properties of monocrystalline microwires of EDT-TTF(CONHMe)(2) and (TMTSF)(2)ClO4 2004 Synthetic Metals   article
Abstract: The monomolecular compound ethylenedithiotetrathiafulvalene (EDT-TTF(CONHMe)(2)) and the charge transfer salt tetramethyltetraselenafulvalene (TMTSF)(2)ClO4 were successfully recrystallized using the drop casting method. Samples of various sizes were obtained, with widths as small as 300 nm and thicknesses above 30 nm. The length of the samples can reach I mm. The conductivity of the former compound, sigmaapproximate to3.10(-7) S cm(-1) is typical of neutral TTF derivatives. Its bulk mobility is about mu(b)approximate to1 cm(2)/Vs. For the thinnest samples of (TMTSF)(2)ClO4, the two point conductivity is dominated by the sample conductivity instead of the contact resistance. (C) 2004 Elsevier B.V. All rights reserved.
BibTeX:
@article{Colin2004,
author = {Colin, C. and Pasquier, C. R. and Auban-Senzier, P. and Restagno, F. and Baudron, S. and Batail, P. and Fraxedas, J.},
title = {Transport properties of monocrystalline microwires of EDT-TTF(CONHMe)(2) and (TMTSF)(2)ClO4},
journal = {Synthetic Metals},
year = {2004},
volume = {146},
number = {3},
pages = {273--277}
}
      
Hamraoui, A., Cachile, M., Poulard, C. & Cazabat, A. M. Fingering phenomena during spreading of surfactant solutions 2004 Colloids And Surfaces A-Physicochemical And Engineering Aspects   article
Abstract: Fingering instabilities are observed at the contact line of drops of surfactant solutions spreading spontaneously Oil solid surfaces coated by a film of solvent. The occurrences of instabilities, and the characteristics of the instability pattern, are controlled by the surfactant concentration and the thickness of the film adsorbed or deposited on the substrate. This work provides experimental data as a basis for forthcoming theoretical analyses. (C) 2004 Elsevier B.V. All rights reserved.
BibTeX:
@article{Hamraoui2004,
author = {Hamraoui, A. and Cachile, M. and Poulard, C. and Cazabat, A. M.},
title = {Fingering phenomena during spreading of surfactant solutions},
journal = {Colloids And Surfaces A-Physicochemical And Engineering Aspects},
year = {2004},
volume = {250},
number = {1-3},
pages = {215--221}
}
      
Laurens, C., Creton, C. & Leger, L. Adhesion promotion mechanisms at isotactic polypropylene/polyamide 6 interfaces: Role of the copolymer architecture 2004 Macromolecules   article
Abstract: The fracture toughness of isotactic polypropylene (iPP)-polyamide 6 (PA6) assemblies, stabilized by diblock copolymers formed in situ during the annealing of the samples, has been investigated as a function of annealing conditions and molecular architecture of the PP part of the copolymer. Comparing the evolutions of the fracture toughness with annealing time annealing temperature and surface density of copolymers for six different architectures, the reinforcement mechanisms could be qualitatively identified. It is thus possible to design an "optimal" copolymer for adhesion reinforcement: it has to have a molecular architecture as close as possible to that of the PP matrix and to be long enough so that it can bridge crystalline lamellae in the PP part of the sample, an effect which is favored when the annealing temperature is above the melting temperature of both parts of the assembly, due to an epitaxial orientation at the PP-PA6 interface.
BibTeX:
@article{Laurens2004,
author = {Laurens, C. and Creton, C. and Leger, L.},
title = {Adhesion promotion mechanisms at isotactic polypropylene/polyamide 6 interfaces: Role of the copolymer architecture},
journal = {Macromolecules},
year = {2004},
volume = {37},
number = {18},
pages = {6814--6822}
}
      
Laurens, C., Ober, R., Creton, C. & Leger, L. Crystalline orientation and adhesion at polypropylene/polamide 6 interfaces compatibilized with syndiotactic polypropylene-polyamide 6 diblock copolymers 2004 Macromolecules   article
Abstract: Assemblies of polyamide 6 (PA6) with both syndiotactic and isotactic polypropylene (sPP and iPP) have been investigated in the presence of sPP-PA6 diblock copolymers formed in situ at the interface during annealing. Both iPP/PA6 and sPP/PA6 interfaces were stabilized by the sPP-PA6 copolymers. Crystalline orientations at the interface, characterized by X-ray diffraction using thin film assemblies, demonstrated an epitaxial crystallization of sPP on PA6, with a degree of orientation of the sPP increasing with increasing cooling rates, annealing times, and temperatures. For iPP/PA6 samples, the sPP-PA6 diblock copolymer had a sufficient stabilizing role on the interface to allow the observation of the iPP/PA6 epitaxy previously described, with a higher sensitivity of the degree of orientation to the annealing time than for sPP/PA6. The adhesive strength of macroscopic assemblies was also measured. The sPP-PA6 copolymer was able to mechanically reinforce the sPP/PA6 interface but not the iPP/PA6 one. The specific orientation of the polymers in the immediate vicinity of the interface is thus not sufficient to promote strong adhesion. The structure of the copolymer and its ability to entangle and probably cocrystallize with the matrix must also be considered.
BibTeX:
@article{Laurens2004a,
author = {Laurens, C. and Ober, R. and Creton, C. and Leger, L.},
title = {Crystalline orientation and adhesion at polypropylene/polamide 6 interfaces compatibilized with syndiotactic polypropylene-polyamide 6 diblock copolymers},
journal = {Macromolecules},
year = {2004},
volume = {37},
number = {18},
pages = {6806--6813}
}
      
Restagno, F., Bocquet, L. & Charlaix, E. Where does a cohesive granular heap break? 2004 European Physical Journal E   article
Abstract: In this paper, we consider the effect of cohesion on the stability of a granular heap and compute the maximum angle of stability of the heap as a function of the cohesion. We show that the stability is strongly affected by the dependence of the cohesion on the local pressure. In particular, this dependence is found to determine the localization of the failure plane. While for a constant adhesion force, slip occurs deep inside the heap, surface failure is obtained for a linear variation of the cohesion on the normal stress. Such a transition allows to interpret some recent experimental results on cohesive materials.
BibTeX:
@article{Restagno2004,
author = {Restagno, F. and Bocquet, L. and Charlaix, E.},
title = {Where does a cohesive granular heap break?},
journal = {European Physical Journal E},
year = {2004},
volume = {14},
number = {2},
pages = {177--183}
}
      
Serghei, A., Hartmann, L., Pouret, P., Leger, L. & Kremer, F. Molecular dynamics in thin (grafted) polymer layers 2004 Colloid And Polymer Science   article
Abstract: Broadband dielectric spectroscopy is employed to study the molecular dynamics in thin polymer layers of (spin-coated) cis-1, 4-polyisoprene (PI) and of (grafted and spin-coated) polydimethylsiloxane (PDMS). For the former, besides the segmental and the normal mode relaxation, a confinement-induced mode is observed, which is assigned to fluctuations of terminal subchains. It turns out that the uptake of water has a strong influence on the dynamics of this relaxation, which takes place in the immediate vicinity of the interface. Between grafted and spin-coated PDMS a pronounced difference in the dynamics is observed for layers that are comparable in thickness to the radius of gyration of the confined chain. This is attributed to the different conformation of grafted and spin-coated polymer layers.
BibTeX:
@article{Serghei2004,
author = {Serghei, A. and Hartmann, L. and Pouret, P. and Leger, L. and Kremer, F.},
title = {Molecular dynamics in thin (grafted) polymer layers},
journal = {Colloid And Polymer Science},
year = {2004},
volume = {282},
number = {8},
pages = {946--954}
}
      
Vilmin, T., Tardivat, C., Leger, L., Brown, H. & Raphael, E. Interdigitation between surface-anchored polymer chains and an elastomer: Consequences for adhesion promotion 2004 Europhysics Letters   article
Abstract: We study the adhesion between a crosslinked elastomer and a flat solid surface where polymer chains have been end-grafted. To understand the adhesive feature of such a system, one has to study both the origin of the grafted layer interdigitation with the network, and the end-grafted chains extraction out of the elastomer when it comes unstuck from the solid surface. We shall tackle here the first aspect for which we develop a partial-interdigitation model that lets us analytically predict a critical surface grafting density sigma(*) similar or equal to P1/10 N-3/5 beyond which only the thermal fluctuations allow the layer to interdigitate with the elastomer. We then relate this result with recent adhesion measurements.
BibTeX:
@article{Vilmin2004,
author = {Vilmin, T. and Tardivat, C. and Leger, L. and Brown, H. and Raphael, E.},
title = {Interdigitation between surface-anchored polymer chains and an elastomer: Consequences for adhesion promotion},
journal = {Europhysics Letters},
year = {2004},
volume = {68},
number = {4},
pages = {543--549}
}
      
Amouroux, N. & Leger, L. Effect of dangling chains on adhesion hysteresis of silicone elastomers, probed by JKR test 2003 Langmuir   article
Abstract: The JKR test has been used to quantify adhesion hysteresis between PDMS model networks having different amount of dangling chains. The adhesion hysteresis G - W appears time dependent, and increases with the amount of dangling chains. In accordance with recent investigations of interactions between a brush and an elastomer, it is believed that this hysteresis comes from the progressive bridging of the interface by pendant chains present in the network.
BibTeX:
@article{Amouroux2003,
author = {Amouroux, N. and Leger, L.},
title = {Effect of dangling chains on adhesion hysteresis of silicone elastomers, probed by JKR test},
journal = {Langmuir},
year = {2003},
volume = {19},
number = {4},
pages = {1396--1401}
}
      
Benichou, O., Cachile, M., Cazabat, A. M., Poulard, C., Valignat, M. P., Vandenbrouck, F. & Van Effenterre, D. Thin films in wetting and spreading 2003 Advances In Colloid And Interface Science   article
Abstract: Thin films differ from bulk phases both from a thermodynamic point of view, i.e. the chemical potential of a molecule in a film depends on the film thickness, and in their dynamical response, because relaxation times may become large in these confined media. Examples of slow structural relaxation in thin films of liquid crystals, and their consequences on the wetting properties of the systems are presented first. Then, we illustrate the thermodynamic specificity of thin films when evaporation is considered. The consequences on the wetting dynamics of macroscopic evaporating droplets are presented in the last part of the paper. (C) 2002 Elsevier Science B.V. All rights reserved.
BibTeX:
@article{Benichou2003,
author = {Benichou, O. and Cachile, M. and Cazabat, A. M. and Poulard, C. and Valignat, M. P. and Vandenbrouck, F. and Van Effenterre, D.},
title = {Thin films in wetting and spreading},
journal = {Advances In Colloid And Interface Science},
year = {2003},
volume = {100},
pages = {381--398}
}
      
Cottin-Bizonne, C., Jurine, S., Baudry, J., Crassous, J., Restagno, F. & Charlaix, E. Influence of the wetting properties on the flow boundary condition at a solid interface 2003 Houille Blanche-Revue Internationale De L Eau   article
Abstract: We report here experiments with a Dynamic Surface Force Apparatus (DSFA) to investigate the flow boundary condition of glycerol at a solid surface. We use hydrophilic Pyrex surfaces and hydrophobic surfaces made of a Self-Assembled Monolayer of OTS (octadecyltrichlorosilane) on Pyrex. The DSFA allows us to study the flow of a liquid film confined between two surfaces with a nanometer resolution. No-slip boundary conditions are found for glycerol on hydrophilic surfaces only. Significant slip is found on the hydrophobic surfaces, with a typical length of one hundred nanometers.
BibTeX:
@article{Cottin-Bizonne2003,
author = {Cottin-Bizonne, C. and Jurine, S. and Baudry, J. and Crassous, J. and Restagno, F. and Charlaix, E.},
title = {Influence of the wetting properties on the flow boundary condition at a solid interface},
journal = {Houille Blanche-Revue Internationale De L Eau},
year = {2003},
number = {5},
pages = {116--119}
}
      
Hartmann, L., Kremer, F., Pouret, P. & Leger, L. Molecular dynamics in grafted layers of poly(dimethylsiloxane) 2003 Journal Of Chemical Physics   article
Abstract: Dielectric relaxation spectroscopy (10(-1) Hz to 10(6) Hz) is employed to study the molecular dynamics of poly(dimethylsiloxane) (PDMS, M-w = 1.7x10(5) g mol(-1) and M-w = 9.6x10(4) g mol(-1)) as grafted films with thicknesses d below and above the radius of gyration R-g. For the thinnest films the molecular dynamics becomes faster by up to two orders of magnitude with respect to the bulk resulting in a pronounced decrease of the Vogel temperature T-0 and hence the calorimetric glass transition temperature T-g. For films with d = 41 nm>R-g the molecular dynamics is comparable to that of the bulk melt. The results are interpreted in terms of a chain confinement effect and compared with findings for low molecular weight glass forming liquids contained in nanoporous materials. Crystallization effects-well known for PDMS-are observed for films of thicknesses above and below R-g. (C) 2003 American Institute of Physics.
BibTeX:
@article{Hartmann2003,
author = {Hartmann, L. and Kremer, F. and Pouret, P. and Leger, L.},
title = {Molecular dynamics in grafted layers of poly(dimethylsiloxane)},
journal = {Journal Of Chemical Physics},
year = {2003},
volume = {118},
number = {13},
pages = {6052--6058}
}
      
Hervet, H. & Leger, L. Flow with slip at the wall: from simple to complex fluids 2003 Comptes Rendus Physique   article
Abstract: We present series of experiments based on a Near Field Laser Velocimetry technique, aimed to characterize friction mechanisms at fluid-solid interfaces. For simple fluids, we show that noticeable slip at the wall can occur in the case of a smooth surface even in total wetting conditions. For polymer fluids, entanglements between surface anchored chains and bulk polymer govern the friction. A dynamical decoupling associated to disentanglements between surface and bulk chains is observed at large enough shear rates, leading to high slip and low friction. More elastomer like polymers lead to stick-slip instabilities in a narrow range of shear rates. To cite this article: H. Hervet, L. Leger, C R. Physique 4 (2003). (C) 2003 Academie des sciences/Editions scientifiques et medicales Elsevier SAS. All rights reserved.
BibTeX:
@article{Hervet2003,
author = {Hervet, H. and Leger, L.},
title = {Flow with slip at the wall: from simple to complex fluids},
journal = {Comptes Rendus Physique},
year = {2003},
volume = {4},
number = {2},
pages = {241--249}
}
      
Kremer, F., Hartmann, L., Serghei, A., Pouret, P. & Leger, L. Molecular dynamics in thin grafted and spin-coated polymer layers 2003 European Physical Journal E   article
Abstract: Broadband Dielectric Spectroscopy is employed to study the molecular dynamics in thin layers of grafted and spin-coated polydimethylsiloxane (PDMS) and of the type-A polymer cis-1,4-polyisoprene (PI). Strong resemblance with low-molecular-weight systems is found but additionally the conformation of the chain and its extension becomes important. For PI a confinement-induced relaxation is found. It is observable if the layer thickness is comparable to the end-to-end vector of the chain and it depends strongly on the separation between interfaces. In contrast, the dynamic (and hence the calorimetric) glass transition is not affected by the geometrical confinement.
BibTeX:
@article{Kremer2003,
author = {Kremer, F. and Hartmann, L. and Serghei, A. and Pouret, P. and Leger, L.},
title = {Molecular dynamics in thin grafted and spin-coated polymer layers},
journal = {European Physical Journal E},
year = {2003},
volume = {12},
number = {1},
pages = {139--142}
}
      
Laurens, C., Ober, R., Creton, C. & Leger, L. Interfaces between semi-crystalline polymers reinforced by diblock copolymers 2003 Annales De Chimie-Science Des Materiaux   article
Abstract: The interface between isotactic polypropylene (iPP) and polyamide 6 (PA6) was studied. We used functionalized: polypropylenes (PPf) able to react with PA6 as compatibilizing agents. The copolymer formation allows the stabilization of the interface and the study of its crystalline orientation. The amount of copolymers at the interface, Sigma, was measured by XPS. The copolymer formation kinetics were thus determined and we show that it strongly depends on the PPf structure. The mechanical strength of the interface, G(c), was-also measured, as a function of the annealing temperature and PPf structure. The coupling between G(c) and Sigma measurements allowed us to determine the reinforcement mechanisms of the interface. We show that the efficiency of high molecular weight copolymers is maximum for annealing temperatures above the melting temperatures of both matrices, whatever the microstructure. This effect is related to the ability of the copolymers to bridge several crystalline lamellae in the epitaxially oriented layer at the interface.
BibTeX:
@article{Laurens2003,
author = {Laurens, C. and Ober, R. and Creton, C. and Leger, L.},
title = {Interfaces between semi-crystalline polymers reinforced by diblock copolymers},
journal = {Annales De Chimie-Science Des Materiaux},
year = {2003},
volume = {28},
number = {3},
pages = {29--42}
}
      
Leger, L. Friction mechanisms and interfacial slip at fluid-solid interfaces 2003 Journal Of Physics-Condensed Matter   article
Abstract: We present series of experiments based on near field laser velocimetry, developed to characterize the friction mechanisms at fluid-solid interfaces. For polymers, entangled polymer melts are sheared against smooth solid surfaces, covered by surface attached polymer chains of the same chemical species, having a controlled surface density. Direct measurements of the interfacial velocity and of the shear force allow identification of the molecular mechanisms of friction. Depending on the value of the inverse of the shear rate experienced by the polymer compared to the reptation time, the transition between a regime of high and a regime of low friction observed when increasing the shear rate can be related to disentanglement or to the extraction of the surface chains from the bulk polymer. Surfaces with adjusted friction properties can thus be designed by choosing chain anchored length and surface density. For simple fluids, the direct measurements of the interfacial velocity show that, contrary to the usual hypothesis of hydrodynamics, a simple fluid can exhibit slip at the wall. Both the surface roughness and the strength of the fluid-solid interactions fix the amplitude of wall slip, acting in an antagonistic way.
BibTeX:
@article{Leger2003,
author = {Leger, L.},
title = {Friction mechanisms and interfacial slip at fluid-solid interfaces},
journal = {Journal Of Physics-Condensed Matter},
year = {2003},
volume = {15},
number = {1},
pages = {S19--S29}
}
      
Lorenceau, E., Restagno, F. & Quere, D. Fracture of a viscous liquid 2003 Physical Review Letters   article
Abstract: When a viscous liquid hits a pool of liquid of the same nature, the impact region is hollowed by the shock. Its bottom becomes extremely sharp if increasing the impact velocity, and we report that the curvature at that place increases exponentially with the flow velocity, in agreement with a theory by Jeong and Moffatt. Such a law defines a characteristic velocity for the collapse of the tip, which explains both the cusplike shape of this region, and the instability of the cusp if increasing (slightly) the impact velocity. Then, a film of the upper phase is entrained inside the pool. We characterize the critical velocity of entrainment of this phase and compare our results with recent predictions by Eggers.
BibTeX:
@article{Lorenceau2003,
author = {Lorenceau, E. and Restagno, F. and Quere, D.},
title = {Fracture of a viscous liquid},
journal = {Physical Review Letters},
year = {2003},
volume = {90},
number = {18},
pages = {184501}
}
      
Poulard, C., Benichou, O. & Cazabat, A. M. Freely receding evaporating droplets 2003 Langmuir   article
Abstract: The evaporation rate of drops of pure, completely wetting liquids is investigated experimentally and theoretically in the situation where no pinning of the contact line is occurring. It is shown that the observed dynamics is controlled by the volatility of the liquid, as expected, but also by the properties of the wetting film left on the substrate. Contact line instabilities and nonmonotonic behavior of the receding contact angle may be observed and are accounted for. However, the water still needs further investigations.
BibTeX:
@article{Poulard2003,
author = {Poulard, C. and Benichou, O. and Cazabat, A. M.},
title = {Freely receding evaporating droplets},
journal = {Langmuir},
year = {2003},
volume = {19},
number = {21},
pages = {8828--8834}
}
      
Bocquet, L., Charlaix, E. & Restagno, F. Physics of humid granular media 2002 Comptes Rendus Physique   article
Abstract: A very small amount of liquid added or condensed from a vapor in a granular heap can induce dramatic changes of its static properties. In this paper we review recent advances in humid granular media. We discuss the first approaches for describing the cohesion forces acting between spherical rough beads, and their effect on the maximum avalanche angle of a granular heap. We also discuss the time dependency of these cohesive forces leading to ageing effects in the properties of the medium. (C) 2002 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.
BibTeX:
@article{Bocquet2002,
author = {Bocquet, L. and Charlaix, E. and Restagno, F.},
title = {Physics of humid granular media},
journal = {Comptes Rendus Physique},
year = {2002},
volume = {3},
number = {2},
pages = {207--215}
}
      
Cachile, M., Benichou, O., Poulard, C. & Cazabat, A. M. Evaporating droplets 2002 Langmuir   article
Abstract: The dynamics of evaporation of drops of simple, completely wetting liquids is investigated experimentally and theoretically in the situation where no pinning of the contact line is occurring. When the contact angle is low enough, it is shown that a convenient approximation for the equation governing the dynamics of the drop is to keep only the evaporation term. The simplified equation has been studied mathematically and numerically. The agreement with experimental data is extremely good, allowing us to address more complex cases involving gradient and hydrodynamic effects.
BibTeX:
@article{Cachile2002,
author = {Cachile, M. and Benichou, O. and Poulard, C. and Cazabat, A. M.},
title = {Evaporating droplets},
journal = {Langmuir},
year = {2002},
volume = {18},
number = {21},
pages = {8070--8078}
}
      
Cottin-Bizonne, C., Jurine, S., Baudry, J., Crassous, J., Restagno, F. & Charlaix, E. Nanorheology: An investigation of the boundary condition at hydrophobic and hydrophilic interfaces 2002 European Physical Journal E   article
Abstract: It has been shown that the flow of a simple liquid over a solid surface can violate the so-called no-slip boundary condition. We investigate the flow of polar liquids, water and glycerol, on a hydrophilic Pyrex surface and a hydrophobic surface made of a Self-Assembled Monolayer of OTS (octadecyltrichlorosilane) on Pyrex. We use a Dynamic Surface Force Apparatus (DSFA) which allows one to study the flow of a liquid film confined between two surfaces with a nanometer resolution. No-slip boundary conditions are found for both fluids on hydrophilic surfaces only. Significant slip is found on the hydrophobic surfaces,with a typical length of one hundred nanometers.
BibTeX:
@article{Cottin-Bizonne2002,
author = {Cottin-Bizonne, C. and Jurine, S. and Baudry, J. and Crassous, J. and Restagno, F. and Charlaix, E.},
title = {Nanorheology: An investigation of the boundary condition at hydrophobic and hydrophilic interfaces},
journal = {European Physical Journal E},
year = {2002},
volume = {9},
number = {1},
pages = {47--53}
}
      
Lau, A. W. C., Portigliatti, M., Raphael, E. & Leger, L. Spreading of latex particles on a substrate 2002 Europhysics Letters   article
Abstract: We have investigated both experimentally and theoretically the spreading behavior of latex particles deposited on solid substrates. These particles, which are composed of cross-linked polymer chains, have an intrinsic elastic modulus. We show that the elasticity must be considered to account for the observed contact angle between the particle and the olid substrate, as measured through atomic-force microscopy techniques. In particular, the work of adhesion computed within our model can be significantly larger than that from the classical Dupre formula.
BibTeX:
@article{Lau2002,
author = {Lau, A. W. C. and Portigliatti, M. and Raphael, E. and Leger, L.},
title = {Spreading of latex particles on a substrate},
journal = {Europhysics Letters},
year = {2002},
volume = {60},
number = {5},
pages = {717--723}
}
      
Leger, L. Friction at polymer-solid and simple fluid-solid interfaces. 2002 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{Leger2002,
author = {Leger, L.},
title = {Friction at polymer-solid and simple fluid-solid interfaces.},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {2002},
volume = {223},
pages = {C56--C56}
}
      
Restagno, F., Bocquet, L., Crassous, J. & Charlaix, E. Slow kinetics of capillary condensation in confined geometry: experiment and theory 2002 Colloids And Surfaces A-Physicochemical And Engineering Aspects   article
Abstract: When two solid surfaces are brought in contact, water vapor present in the ambient air may condense in the region of the contact to form a liquid bridge connecting the two surfaces: this is the so-called capillary condensation. This phenomenon has drastic consequences on the contact between solids, modifying the macroscopic adhesion and friction properties. In this paper, we present a survey of the work we have performed both experimentally and theoretically to understand the microscopic foundations of the kinetics of capillary condensation. From the theoretical point of view, we have computed the free energy barrier associated with the condensation of the liquid from the gas in a confined system. These calculations allow understanding of the existence of very large hysteresis, which is often associated with capillary condensation. These results are compatible with experimental results obtained with a surface forces apparatus in a vapor atmosphere, showing a large hysteresis of the surface energy of two parallel planes as a function of their distance. In the second part, we present some experiments on the influence of humidity on the avalanche angle of granular media. We show that the aging in time of this avalanche angle can be explained by the slow kinetics of capillary condensation in a random confined geometry. (C) 2002 Elsevier Science B.V. All rights reserved.
BibTeX:
@article{Restagno2002b,
author = {Restagno, F. and Bocquet, L. and Crassous, J. and Charlaix, E.},
title = {Slow kinetics of capillary condensation in confined geometry: experiment and theory},
journal = {Colloids And Surfaces A-Physicochemical And Engineering Aspects},
year = {2002},
volume = {206},
number = {1-3},
pages = {69--77}
}
      
Restagno, F., Crassous, J., Charlaix, E., Cottin-Bizonne, C. & Monchanin, M. A new surface forces apparatus for nanorheology 2002 Review Of Scientific Instruments   article
Abstract: We present an original surface forces apparatus which enables us to measure the interaction forces between any solid surfaces such as, e.g., metallic surfaces, opaque surfaces, or rough surfaces. The relative displacement of the surfaces is measured with a capacitive sensor. The forces are measured by a stiff and highly sensitive interferometric sensor. The measurements are performed in a dc to 100 Hz bandwidth. This feature allows us to study the mechanical response of a nanometric confined medium to rapid strain variations in the linear regime. An example of nanorheological measurement of dodecane confined in a nanometric gap is given at the end of this article. (C) 2002 American Institute of Physics.
BibTeX:
@article{Restagno2002a,
author = {Restagno, F. and Crassous, J. and Charlaix, E. and Cottin-Bizonne, C. and Monchanin, M.},
title = {A new surface forces apparatus for nanorheology},
journal = {Review Of Scientific Instruments},
year = {2002},
volume = {73},
number = {6},
pages = {2292--2297}
}
      
Restagno, F., Crassous, J., Cottin-Bizonne, C. & Charlaix, E. Adhesion between weakly rough beads 2002 Physical Review E   article
Abstract: Cohesion effects are of prime importance in powders and granular media, and they are strongly affected by the roughness of the grain surface. We report measurements of the adhesion force between surfaces of Pyrex having a nanometric roughness, with a surface force apparatus. The two surfaces are immersed in liquid n-dodecane. The adhesion force measured is much smaller than expected in the case of smooth surfaces. We find that the adhesion force depends on the maximal load that has been applied on the surfaces, but does not depend on the time during which they have been in contact. We propose a model of plastic deformation of the small asperities in a macroscopic Hertz contact which is in good agreement with the experimental data.
BibTeX:
@article{Restagno2002,
author = {Restagno, F. and Crassous, J. and Cottin-Bizonne, C. and Charlaix, E.},
title = {Adhesion between weakly rough beads},
journal = {Physical Review E},
year = {2002},
volume = {65},
number = {4},
pages = {042301}
}
      
Restagno, F., Ursini, C., Gayvallet, H. & Charlaix, E. Aging in humid granular media 2002 Physical Review E   article
Abstract: Aging behavior is an important effect in the friction properties of solid surfaces. In this paper we investigate the temporal evolution of the static properties of a granular medium by studying the aging over time of the maximum stability angle of submillimetric glass beads. We report the effect of several parameters on these aging properties, such as the wear on the beads, the stress during the resting period, and the humidity content of the atmosphere. Aging effects in an ethanol atmosphere are also studied. These experimental results are discussed at the end of the paper.
BibTeX:
@article{Restagno2002c,
author = {Restagno, F. and Ursini, C. and Gayvallet, H. and Charlaix, E.},
title = {Aging in humid granular media},
journal = {Physical Review E},
year = {2002},
volume = {66},
number = {2},
pages = {021304}
}
      
Amouroux, N., Petit, J. & Leger, L. Role of interfacial resistance to shear stress on adhesive peel strength 2001 Langmuir   article
Abstract: The adherence of an acrylic tape on silicone elastomers containing various quantities of a silicone MQ resin has been investigated by an instrumented peel test, along the lines of Newby and Chaudhury's work (Langmuir 1997,13,1805-1809; Langmuir 1998,14,4865-4872), which gave the first evidence of interfacial slip when a pressure-sensitive adhesive is peeled from a thin poly(dimethylsiloxane) (PDMS) layer. In the present study, we show that the amplitude of interfacial slip movements is correlated to the composition of the elastomer in MQ resin (small silica-like particles inserted into the elastomer). High slip amplitudes are associated with low MQ resin content and result in weak shear deformations in the adhesive. Thus, depending on the composition of the elastomer, the peel energy is dominated either by frictional losses associated with slip at the interface (low MQ resin content) or by viscous dissipation due to shear deformations distributed in the volume of the adhesive (high MQ resin content). The transition between these two processes depends on the contact time between the acrylic tape and the elastomer prior to peeling. The viscous and the frictional parts of the dissipated energy are quantitatively estimated from the observed displacements at the interface and within the adhesive, the shear modulus of the adhesive, and frictional laws determined from "pure" shear experiments. The computed energies can represent half of the measured peel energy for this adjustable slip system. The understanding of the molecular mechanisms involved should help in the design of surfaces with adjusted adhesive properties.
BibTeX:
@article{Amouroux2001,
author = {Amouroux, N. and Petit, J. and Leger, L.},
title = {Role of interfacial resistance to shear stress on adhesive peel strength},
journal = {Langmuir},
year = {2001},
volume = {17},
number = {21},
pages = {6510--6517}
}
      
Kalb, F., Leger, L., Creton, C., Plummer, C. J. G., Marcus, P. & Magalhaes, A. Molecular control of crack tip plasticity mechanisms at a PP-EPDM/PA6 interface 2001 Macromolecules   article
Abstract: Adhesion between polyamide 6 (PA6) and thermoplastic vulcanizates in which the continuous phase is polypropylene (PP) have been investigated through double beam cantilever tests. Both a precise control, on molecular scales, of the surface density of bloc copolymer molecules acting as adhesion promoters and systematic observation (for scales ranging from nano- to micrometric) of the plastic deformation zones developing at the crack tip are used to identify the adhesion mechanisms. As long as the plastic deformation zones remain localized Dugdale type zones, the adhesive strength is driven by the surface density of the copolymer molecules at the interface and quantitatively follows the Brown model, whatever the detailed architecture of the crack tip deformation zone.
BibTeX:
@article{Kalb2001,
author = {Kalb, F. and Leger, L. and Creton, C. and Plummer, C. J. G. and Marcus, P. and Magalhaes, A.},
title = {Molecular control of crack tip plasticity mechanisms at a PP-EPDM/PA6 interface},
journal = {Macromolecules},
year = {2001},
volume = {34},
number = {8},
pages = {2702--2709}
}
      
Laurens, C., Ober, R., Creton, C. & Leger, L. Role of the interfacial orientation in adhesion between semicrystalline polymers 2001 Macromolecules   article
Abstract: To understand the molecular mechanisms responsible for the adhesion between isotactic polypropylene (iPP) and polyamide 6 (PA6) ix the presence of iPP-PA6 diblock copolymer, thin film assemblies with a typical thickness of 115 nm have been prepared. The crystalline orientation of the iPP and of the PA6 close to the interface has been investigated by X-ray diffraction. An epitaxial crystallization of iPP on PA6 was observed. Similarly to what happens for adhesive strength, the epitaxy is enhanced when increasing the copolymer surface density or the length of the PP block and further enhanced when the samples were annealed above the melting temperature of PA6.
BibTeX:
@article{Laurens2001,
author = {Laurens, C. and Ober, R. and Creton, C. and Leger, L.},
title = {Role of the interfacial orientation in adhesion between semicrystalline polymers},
journal = {Macromolecules},
year = {2001},
volume = {34},
number = {9},
pages = {2932--2936}
}
      
Leger, L., Hervet, H., Charitat, T. & Koutsos, V. The stick-slip transition in highly entangled poly( styrene-butadiene) melts 2001 Advances In Colloid And Interface Science   article
Abstract: We study the interfacial slippage of highly viscous polymer melts in a plane Couette cell by combining stress measurements and optical determination of sliding velocities (Fluorescence Recovery After Photobleaching). This enables us to observe the apparition of stick-slip instabilities in a narrow shear rate range whose limits are governed by the molecular characteristics of both the bulk and surface anchored polymer chains. A qualitative interpretation of these results will be given in terms of extraction and re-entanglement of the surface anchored chains from the bulk ones as well as a necessary criterion for the apparition of these instabilities. Experiments exploring the kinetics of the stick-slip regime appear to be a simple and promising way to investigate interfacial dynamics and to estimate the characteristic times involved. (C) 2001 Elsevier Science B.V. All rights reserved.
BibTeX:
@article{Leger2001,
author = {Leger, L. and Hervet, H. and Charitat, T. and Koutsos, V.},
title = {The stick-slip transition in highly entangled poly( styrene-butadiene) melts},
journal = {Advances In Colloid And Interface Science},
year = {2001},
volume = {94},
number = {1-3},
pages = {39--52}
}
      
Marzolin, C., Auroy, P., Deruelle, M., Folkers, J. P., Leger, L. & Menelle, A. Neutron reflectometry study of the segment-density profiles in end-grafted and irreversibly adsorbed layers of polymer in good solvents 2001 Macromolecules   article
Abstract: The segment density profile of anchored layers of poly(dimethylsiloxane) in good solvents has been measured using neutron reflectometry. Two types of layers have been studied: end-grafted layers (brushes) and irreversibly adsorbed layers, on silicon/silicon dioxide. The latter can be viewed as a polydisperse brush of loops and was obtained by adsorbing the polymer from the melt or from a concentrated solution. A model-free constrained fitting procedure was developed, which gave the concentration profile with a good precision. We present this numerical method and the concentration profiles obtained for the different layers. The profiles of the two types of layers are significantly different. They are in agreement with self-consistent mean field theory for the brushes and with scaling laws descriptions for the irreversibly adsorbed layers. The reflectivity measurement enabled us to verify precisely that the concentration profile in the brush cannot be described by a step function with a Gaussian roughness but has a parabolic shape.
BibTeX:
@article{Marzolin2001,
author = {Marzolin, C. and Auroy, P. and Deruelle, M. and Folkers, J. P. and Leger, L. and Menelle, A.},
title = {Neutron reflectometry study of the segment-density profiles in end-grafted and irreversibly adsorbed layers of polymer in good solvents},
journal = {Macromolecules},
year = {2001},
volume = {34},
number = {25},
pages = {8694--8700}
}
      
Pit, R., Hervet, H. & Leger, L. Direct experimental evidences for flow with slip at hexadecane - solid interfaces 2001 Revue De Metallurgie-Cahiers D Informations Techniques   article
Abstract: The limit condition for the flow rate at the wall for a Newtonian fluid with various solid/liquid interfaces was studied experimentally using an original high resolution technique. A notable interfacial slipping was shown for the hexadecane flowing on a surface with low roughness and covered with methyl groups (non wetting surface for the hexadecane). The systematic study of various modified surfaces made it possible to identify two key parameters fixing the amplitude of slipping at the wall and acting in an antagonistic way on the roughness of the surface (geometric and chemical) and the fluid/surface interactions.
BibTeX:
@article{Pit2001,
author = {Pit, R. and Hervet, H. and Leger, L.},
title = {Direct experimental evidences for flow with slip at hexadecane - solid interfaces},
journal = {Revue De Metallurgie-Cahiers D Informations Techniques},
year = {2001},
volume = {98},
number = {2},
pages = {169--+}
}
      
Restagno, F., Crassous, J., Charlaix, E. & Monchanin, M. A new capacitive sensor for displacement measurement in a surface-force apparatus 2001 Measurement Science & Technology   article
Abstract: We present a new capacitive sensor for displacement measurement in a surface-force apparatus which allows dynamical measurements in the range 0-100 Hz. This sensor measures the relative displacement between two macroscopic opaque surfaces over periods of time ranging from milliseconds to, in principle, an indefinite period, at a very low price and down to atomic resolution. It consists of a plane capacitor, a high frequency oscillator and a high sensitivity frequency-to-voltage converter. We use this sensor to study the nanorheological properties of dodecane confined between glass surfaces.
BibTeX:
@article{Restagno2001,
author = {Restagno, F. and Crassous, J. and Charlaix, E. and Monchanin, M.},
title = {A new capacitive sensor for displacement measurement in a surface-force apparatus},
journal = {Measurement Science \& Technology},
year = {2001},
volume = {12},
number = {1},
pages = {16--22}
}
      
Tardivat, C., Hervet, H. & Leger, L. Adhesion evaluation for a stratified system in JKR geometry 2001 Journal Of Adhesion Science And Technology   article
Abstract: The JKR test, which consists of investigating the contact between an elastic lens and a rigid substrate, is a local and precise adhesion test. However, in the classical JKR mechanical analysis, the dimensions of the system must be large compared to the size of the contact area; we consider here a rigid substrate coated with a thin layer of a softer material. We show that this case cannot be analysed using the JKR theory. We propose a simple mechanical approach, modeling the layer as an elastic mattress, which accounts for the experimentally observed phenomena.
BibTeX:
@article{Tardivat2001,
author = {Tardivat, C. and Hervet, H. and Leger, L.},
title = {Adhesion evaluation for a stratified system in JKR geometry},
journal = {Journal Of Adhesion Science And Technology},
year = {2001},
volume = {15},
number = {9},
pages = {1055--1078}
}
      
Zitha, P. L. J., Chauveteau, G. & Leger, L. Unsteady-state flow of flexible polymers in porous media 2001 Journal Of Colloid And Interface Science   article
Abstract: In this paper we report an investigation of the unsteady-state flow of polymer solutions through granular porous media. The experiments were performed using high-molecular-weight nonionic and anionic polyacrylamides dissolved in water containing NaCl and model porous media obtained by packing silicon carbide (SiC) grains having a narrow grain size distribution. Before injection in porous media, the polymer solutions were carefully filtered according to a method that was proved to be efficient in removing any possibly remaining microgels, The SIC grain surface was passively oxidized by a controlled thermal treatment in order to obtain a surface partially covered by a thin silica layer having adsorption properties similar to those of quartzitic sand. By packing SiC grains of different sizes, porous media having identical adsorption properties and well-known pore throats sizes can be obtained with a good reproducibility. Parameters investigated include pore size, velocity gradient, polymer concentration, and adsorption energy. A striking unsteady-state flow behavior (pressure build-up at constant Row rate) is observed when three conditions are fulfilled: (a) the velocity gradient is larger than that known to be able to induce a coil-stretch transition, (b) the polymer adsorbs on the pore surfaces, and (c) the length of stretched macromolecules is larger than the effective pore throat diameter. When one of these conditions is not satisfied the Row remains steady. These observations are interpreted by a mechanism involving the adsorption and bridging across pore restrictions of elongated chains. We propose to refer to this peculiar mode of polymer adsorption as bridging adsorption, (C) 2001 Academic Press.
BibTeX:
@article{Zitha2001,
author = {Zitha, P. L. J. and Chauveteau, G. and Leger, L.},
title = {Unsteady-state flow of flexible polymers in porous media},
journal = {Journal Of Colloid And Interface Science},
year = {2001},
volume = {234},
number = {2},
pages = {269--283}
}
      
Leger, L. Adhesion promotion through controlled surface modifications 2000 Macromolecular Symposia   article
Abstract: We present and discuss series of experiments conducted on systems controlled at the molecular level in order to identify the molecular mechanisms of polymer adhesion. A special emphasis is paid to 1) adhesion enhancement through block copolymers at an interface between two incompatible polymers (amorphous or semi-crystalline); 2) adhesion promotion between an elastomer and a solid, by soft end grafted connector polymer molecules able to interdigitate into the elastomer. We show that surface modifications based on surface anchored polymer chains are efficient for adhesion enhancement because they allow the interface to sustain mechanical stresses. The coupling between surface and bulk stresses is finally what governs the adhesion energy and we examine how one can understand and optimize this coupling.
BibTeX:
@article{Leger2000,
author = {Leger, L.},
title = {Adhesion promotion through controlled surface modifications},
journal = {Macromolecular Symposia},
year = {2000},
volume = {149},
pages = {197--205}
}
      
Pit, R., Hervet, H. & Leger, L. Direct experimental evidence of slip in hexadecane: Solid interfaces 2000 Physical Review Letters   article
Abstract: The boundary condition for the flow velocity of a Newtonian fluid near a solid wall has been probed experimentally with a novel setup using total internal reflection-fluorescence recovery after photobleaching leading to a resolution from the wall of the order of 80 nm. For hexadecane flowing on a hydrocarbon/lyophobic smooth surface, we give what we think to be the first direct experimental evidence of noticeable slip at the wall. We show that the surface roughness and the strength of the fluid-surface interactions both act on wall slip, in antagonist ways.
BibTeX:
@article{Pit2000,
author = {Pit, R. and Hervet, H. and Leger, L.},
title = {Direct experimental evidence of slip in hexadecane: Solid interfaces},
journal = {Physical Review Letters},
year = {2000},
volume = {85},
number = {5},
pages = {980--983}
}
      
Portigliatti, M., Hervet, H. & Leger, L. Nanotack test: adhesive behavior of single latex particles 2000 Comptes Rendus De L Academie Des Sciences Serie Iv Physique Astrophysique   article
Abstract: We present an investigation of the adhesive properties of latex films with nanometric thickness through force spectroscopy using an atomic force microscope (AFM). The AFM tip can be used to indent and excite mechanically one single latex particle, and provides an adhesion test which resembles macroscopic probe tack test, but at nanometric scales. We show that this AFM nanotack test can be analyzed quantitatively, normalizing the total rupture energy by the contact area formed during the indentation step. This contact area depends upon the mechanical properties and environment of the latex particle. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.
BibTeX:
@article{Portigliatti2000,
author = {Portigliatti, M. and Hervet, H. and Leger, L.},
title = {Nanotack test: adhesive behavior of single latex particles},
journal = {Comptes Rendus De L Academie Des Sciences Serie Iv Physique Astrophysique},
year = {2000},
volume = {1},
number = {9},
pages = {1187--1196}
}
      
Portigliatti, M., Koutsos, V., Hervet, H. & Leger, L. Adhesion and deformation of a single latex particle 2000 Langmuir   article
Abstract: The rupture of contact between a single latex particle and an atomic force microscope tip has been investigated at nanoscopic scales by monitoring retracting force-distance curves. The particle is highly elongated, and an intermittent rupture proceeds at the tip/latex interface. The minimal force of detachment, the separation energy, and the long distance shape of the curve depend on the tip velocity and are strongly sensitive to the presence of nearby particles. This indicates that viscoelastic dissipations occur over spatial scales depending on the particles organization. The formation of long nanofilaments seems to be a specific dissipative mechanism prominent for isolated particles.
BibTeX:
@article{Portigliatti2000a,
author = {Portigliatti, M. and Koutsos, V. and Hervet, H. and Leger, L.},
title = {Adhesion and deformation of a single latex particle},
journal = {Langmuir},
year = {2000},
volume = {16},
number = {16},
pages = {6374--6376}
}
      
Restagno, F., Bocquet, L. & Biben, T. Metastability and Nucleation in Capillary Condensation 2000 Phys. Rev. Lett.   article
Abstract: This paper is devoted to thermally activated dynamics of capillary condensation. On the basis of a simple model we identify the critical nucleus involved in the transition mechanism and calculate the nucleation barrier from which we obtain information on the nucleation time. Close to the condensation point, the theory predicts extremely large energy barriers leading to strong metastabilities, long time dependencies, and large hysteresis in agreement with experimental observations in mesoporous media. The validity of the model is assessed using a numerical simulation of a time-dependent Ginzburg-Landau model for the confined system.
BibTeX:
@article{Restagno2000,
author = {F. Restagno AND L. Bocquet AND T. Biben},
title = {Metastability and Nucleation in Capillary Condensation},
journal = {Phys. Rev. Lett.},
year = {2000},
volume = {84},
number = {11},
pages = {2433-36}
}
      
Abstract: This paper is devoted to thermally activated dynamics of capillary condensation. On the basis of a simple model we identify the critical nucleus involved in the transition mechanism and calculate the nucleation barrier from which we obtain information on the nucleation time. Close to the condensation point, the theory predicts extremely large energy barriers leading to strong metastabilities, long time dependencies, and large hysteresis in agreement with experimental observations in mesoporous media. The validity of the model is assessed using a numerical simulation of a time-dependent Ginzburg-Landau model for the confined system.
BibTeX:
@article{Restagno2000a,
author = {Restagno, F. and Bocquet, L. and Biben, T.},
title = {Metastability and nucleation in capillary condensation},
journal = {Physical Review Letters},
year = {2000},
volume = {84},
number = {11},
pages = {2433--2436}
}
      
Restagno, F., Bocquet, L., Biben, T. & Charlaix, E. Thermally activated dynamics of capillary condensation 2000 Journal Of Physics-Condensed Matter   article
Abstract: This paper is devoted to the thermally activated dynamics of capillary condensation. We present a simple model which enables us to identify the critical nucleus involved in the transition mechanism. This simple model is then applied to calculate the nucleation barrier from which we can obtain information on the nucleation time. We present a simple estimation of the nucleation barrier in slab geometry both in the two-dimensional case and in the three-dimensional case. We extend the model to the case of rough surfaces which is closer to the experimental case and allows comparison with experimental data.
BibTeX:
@article{Restagno2000b,
author = {Restagno, F. and Bocquet, L. and Biben, T. and Charlaix, E.},
title = {Thermally activated dynamics of capillary condensation},
journal = {Journal Of Physics-Condensed Matter},
year = {2000},
volume = {12},
number = {8A},
pages = {A419--A424}
}
      
Leger, L., Raphael, E. ; Hervet, H. Surface-Anchored Polymer Chains: Their Role in Adhesion and Friction 1999 Advances in Polymer Science   article
Abstract: Polymer surfaces and interfaces have many technological applications. In the present article we review some recent experiments conducted on model systems with the aim of understanding the role played by surface-anchored polymer layers in adhesion and friction. We also discuss some of the related theoretical models. The key parameter for both situations is the degree of interdigitation between the surface layer and the bulk polymer system (an elastomer in the case of adhesion, a molten polymer in the case of friction). We analyze how this degree of interdigitation governs the optimum enhancement in the adhesion energy between the solid wall and an elastomer, and how it is at the origin of the various wall slip regimes observed experimentally.
BibTeX:
@article{Leger1999b,
  author = {Liliane Lger AND Elie Raphal AND Hubert Hervet},
  title = {Surface-Anchored Polymer Chains: Their Role in Adhesion and Friction},
  journal = {Advances in Polymer Science},
  year = {1999},
  volume = {138/1999},
  number = {Polymers, Interfaces, Grafted chains, Adsorbed chains, Polymer brushes, Adhesion, Friction, Chains pull out, Slip at the wall},
  pages = {185-225}
}
Leger, L., Raphael, E. & Hervet, H. Surface-anchored polymer chains: Their role in adhesion and friction 1999 Polymers In Confined Environments   article
Abstract: Polymer surfaces and interfaces have many technological applications. In the present article we review some recent experiments conducted on model systems with the aim of understanding the role played by surface-anchored polymer layers in adhesion and friction. We also discuss some of the related theoretical models. The key parameter for both situations is the degree of interdigitation between the surface layer and the bulk polymer system tan elastomer in the case of adhesion, a molten polymer in the case of friction). We analyze how this degree of interdigitation governs the optimum enhancement in the adhesion energy between the solid wall and an elastomer, and how it is at the origin of the various wall slip regimes observed experimentally.
BibTeX:
@article{Leger1999,
author = {Leger, L. and Raphael, E. and Hervet, H.},
title = {Surface-anchored polymer chains: Their role in adhesion and friction},
journal = {Polymers In Confined Environments},
year = {1999},
volume = {138},
pages = {185--225}
}
      
Pit, R., Hervet, H. & Leger, L. Flow with slip at the wall for a simple liquid on lyophobic surfaces 1999 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{Pit1999,
author = {Pit, R. and Hervet, H. and Leger, L.},
title = {Flow with slip at the wall for a simple liquid on lyophobic surfaces},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1999},
volume = {217},
pages = {U602--U602}
}
      
Pit, R., Hervet, H. & Leger, L. Slip at the wall for simple liquids on lyophobic surface. 1999 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{Pit1999a,
author = {Pit, R. and Hervet, H. and Leger, L.},
title = {Slip at the wall for simple liquids on lyophobic surface.},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1999},
volume = {218},
pages = {U467--U467}
}
      
Pit, R., Hervet, H. & Leger, L. Friction and slip of a simple liquid at a solid surface 1999 Tribology Letters   article
Abstract: We report a novel experimental technique using total internal reflection - fluorescence recovery after photobleaching (TIR-FRAP) to probe the velocity of a liquid near a wall with a resolution of the order of 100 nm. As an example of use, we have investigated the boundary condition of the liquid velocity during lubricated friction and studied the influence of a classical additive (stearic acid) in a base oil (hexadecane), and demonstrate that simple Newtonian fluids can develop slip at the wall.
BibTeX:
@article{Pit1999b,
author = {Pit, R. and Hervet, H. and Leger, L.},
title = {Friction and slip of a simple liquid at a solid surface},
journal = {Tribology Letters},
year = {1999},
volume = {7},
number = {2-3},
pages = {147--152}
}
      
Woerdeman, D. L., Amouroux, N., Ponsinet, V., Jandeau, G., Hervet, K. & Leger, L. Characterization of glass-epoxy adhesion using JKR methods and atomic force microscopy 1999 Composites Part A-Applied Science And Manufacturing   article
Abstract: The adhesion between an industrial-grade epoxy elastomer and a silanated glass surface was studied using the JKR (lohnson, Kendall and Roberts) technique. Both short-term and longer-term interactions were monitored between the two components. Different silane coupling agents and coating procedures are applied to the glass surfaces, and their effects on the adhesion measurements are investigated. The topography of the silanated surfaces was studied using atomic force microscopy, and correlations were made with the JKR adhesion data. An extensive error analysis was also conducted in an attempt to extract the deterministic content of the data from experimental scatter. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
BibTeX:
@article{Woerdeman1999,
author = {Woerdeman, D. L. and Amouroux, N. and Ponsinet, V. and Jandeau, G. and Hervet, K. and Leger, L.},
title = {Characterization of glass-epoxy adhesion using JKR methods and atomic force microscopy},
journal = {Composites Part A-Applied Science And Manufacturing},
year = {1999},
volume = {30},
number = {1},
pages = {95--109}
}
      
Deruelle, M., Hervet, H., Jandeau, G. & Leger, L. Some remarks on JKR experiments 1998 Journal Of Adhesion Science And Technology   article
Abstract: Two important questions on the validity of the mechanical analysis commonly used to deduce adhesion strength from a Johnson, Kendall and Roberts. (JKR) test are investigated in detail, based on systematic experiments conducted on a JKR machine which allows the relations between the contact area and the load, and between the deformation in the centre of the contact area and the load to be simultaneously characterized. First, the existence of finite size effects associated with the use of small elastomer lenses is clearly demonstrated, and a way to eliminate them is proposed by intercalating an elastomer ribbon with an adjusted thickness between the lens and the rigid plate which holds it. Second, kinetic effects associated with the fact that the unloading sequence is never performed at a vanishing velocity are also analysed. It is shown that a constant and very low unloading rate is not a guarantee that the fracture will propagate at a constant speed. Thus, if the adhesion strength is velocity-dependent, care has to be taken to ensure a correct analysis of the data. It is shown that monitoring the full relaxation trajectory, at fixed deformation, allows such an adhesion strength to be characterized as a function of the velocity.
BibTeX:
@article{Deruelle1998,
author = {Deruelle, M. and Hervet, H. and Jandeau, G. and Leger, L.},
title = {Some remarks on JKR experiments},
journal = {Journal Of Adhesion Science And Technology},
year = {1998},
volume = {12},
number = {2},
pages = {225--247}
}
      
Massey, G., Hervet, H. & Leger, L. Investigation of the slip transition at the melt polymer interface 1998 Europhysics Letters   article
Abstract: We present a detailed experimental investigation of the effect of molecular parameters on the onset of strong slip at the wall for polydimethylsiloxane melts flowing against silica surfaces on which a weak density of polymer chains are anchored by adsorption. The observed variation of the critical velocity for the onset of strong slip V* proportional to N-1.09 P-3.2, With N and P the polymerisation indices of surface and bulk chains, respectively, and the wide range of the non-linear friction regime above V* strongly support the description of the dynamic de-coupling between the surface and bulk chains in terms of progressive disentanglement.
BibTeX:
@article{Massey1998,
author = {Massey, G. and Hervet, H. and Leger, L.},
title = {Investigation of the slip transition at the melt polymer interface},
journal = {Europhysics Letters},
year = {1998},
volume = {43},
number = {1},
pages = {83--88}
}
      
Plummer, C. J. G., Kausch, H. H., Creton, C., Kalb, F. & Leger, L. Structure and microdeformation of (iPP/iPP-g-MA)-PA6 reaction bonded interfaces 1998 Macromolecules   article
Abstract: Transmission electron microscopy has been used in conjunction with RuO4 staining to investigate the structure of (iPP/iPP-g-MA)-PA6 reaction bonded interfaces and microdeformation at interfaces which had failed by crack propagation along the interface. In relatively weak interfaces, the crack tip was preceded by a single, well-defined crazelike fibrillar deformation zone on the iPP/iPP-g-MA side of the interface, with fibril diameters of between 10 and 15 nm. The crack tip itself also propagated along the interface, providing some justification for the extension of established models for interfacial failure in glassy polymers to the present case of two semicrystalline polymers. In stronger interfaces, however, considerable diffuse deformation was observed to accompany crack propagation. This was accounted for by the deeper penetration of the damage zone into the iPP/iPP-g-MA, into regions where the microstructure was less well ordered than immediately adjacent to the interface. This transition from a well-defined to a diffuse damage zone may modify the relationship between the local interfacial strength and the global fracture toughness.
BibTeX:
@article{Plummer1998,
author = {Plummer, C. J. G. and Kausch, H. H. and Creton, C. and Kalb, F. and Leger, L.},
title = {Structure and microdeformation of (iPP/iPP-g-MA)-PA6 reaction bonded interfaces},
journal = {Macromolecules},
year = {1998},
volume = {31},
number = {18},
pages = {6164--6176}
}
      
Restagno, F., Gayvallet, H., Bocquet, L. & Charlaix, E. Humidity Effects and Aging Behavior in Granular Media 1998 Dynamics in Small Confining Systems IV   inproceedings
BibTeX:
@inproceedings{Restagno98,
author = {F. Restagno AND H. Gayvallet AND L. Bocquet AND E. Charlaix},
title = {Humidity Effects and Aging Behavior in Granular Media},
booktitle = {Dynamics in Small Confining Systems {IV}},
year = {1998},
volume = {543}
}
      
Boucher, E., Folkers, J. P., Creton, C., Hervet, H. & Leger, L. Enhanced adhesion between polypropylene and polyamide-6: Role of interfacial nucleation of the beta-crystalline form of polypropylene 1997 Macromolecules   article
Abstract: We present an investigation of the mechanisms of mechanical reinforcement at interfaces between polypropylene (PP) and polyamide-6 (PA6), associated with the incorporation of a small amount of maleic anhydride functionalized PP (PP-g-MA) which reacts with the NH2 groups of the PA6 to form a copolymer in situ. In a previous study we have demonstrated, for one molecular weight of PP-g-MA, that diblock copolymer molecules were indeed formed at the interface, with an areal density Sigma, controlled by the reaction temperature and the reaction time, and that the measured fracture toughness of the interface scaled as G(c) proportional to Sigma(2), regardless of the reaction temperature, but for similar sample cooling conditions. We report here the behavior of the same system for a higher molecular weight PP-g-MA: at a reaction temperature above 220 degrees C, very close to the melting point of the PA6, and above a given Sigma, the measured G(c) becomes 4 times higher than that for reaction temperatures below 220 degrees C, where the observed G, values are identical to what has been measured for the low molecular weight PP-g-MA. G(c) is therefore no longer uniquely dependent on C. Crystallographic analysis on the PP side of the intel face showed a correlation between the presence of the PP beta-phase in the 20 mu m near the interface and a high toughness; this crystalline phase was not present in the samples prepared at T less than or equal to 220 degrees C or with the low molecular weight PP-g-MA which always exhibited a low toughness even for samples prepared above 220 degrees C. It is argued that the presence of this beta phase of the PP is the main factor responsible for the very high fracture toughness, first evidence of the influence of the crystallinity of a semi crystalline polymer on its adhesive properties.
BibTeX:
@article{Boucher1997,
author = {Boucher, E. and Folkers, J. P. and Creton, C. and Hervet, H. and Leger, L.},
title = {Enhanced adhesion between polypropylene and polyamide-6: Role of interfacial nucleation of the beta-crystalline form of polypropylene},
journal = {Macromolecules},
year = {1997},
volume = {30},
number = {7},
pages = {2102--2109}
}
      
Durliat, E., Hervet, H. & Leger, L. Influence of grafting density on wall slip of a polymer melt on a polymer brush 1997 Europhysics Letters   article
Abstract: We have investigated the shear flow of a polydimethylsiloxane (PDMS) melt on a PDMS brush of well-controlled density. As the shear rate, (gamma) over dot, is increased, we show the existence of a slip transition from a weak slip regime, where the extrapolation length of the velocity profile, b, is a constant b(0), to a strong one, where (gamma) over dot sticks to its valve at the transition (gamma) over dot(k). We discuss the influence of the grafting density Sigma on b(0) and (gamma) over dot *. We compare our results with a recent microscopic model.
BibTeX:
@article{Durliat1997,
author = {Durliat, E. and Hervet, H. and Leger, L.},
title = {Influence of grafting density on wall slip of a polymer melt on a polymer brush},
journal = {Europhysics Letters},
year = {1997},
volume = {38},
number = {5},
pages = {383--388}
}
      
Leger, L. Surface anchored polymer: Role in adhesion and friction 1997 Macromolecular Symposia   article
Abstract: We present an investigation of thin polymer layers formed by either strong adsorption or end grafting on a surface or an interface. Depending on the kind of surface attachment, different internal organisations of the chains are observed: either polydisperse loops for adsorbed layers, or almost monodisperse tails in the case of grafting. The molecular parameters of the layer (length and surface density of anchored chains) and the molecular organisation inside the layer govern the ability of the surface anchored chains to be swollen by a good solvent or to penetrate into a bulk polymer, either a melt or a cross-linked elastomer, three properties which have been characterised through neutrons reflectivity techniques. We then analyse how the ability of the surface anchored chains to penetrate into a bulk polymer, entangle with it, and then be deformed when this bulk polymer is mechanically solicitated, are key parameters which govern adhesion and friction properties.
BibTeX:
@article{Leger1997a,
author = {Leger, L.},
title = {Surface anchored polymer: Role in adhesion and friction},
journal = {Macromolecular Symposia},
year = {1997},
volume = {121},
pages = {263--267}
}
      
Leger, L., Hervet, H. & Massey, G. The role of attached polymer molecules in wall slip 1997 Trends In Polymer Science   article
Abstract: High molecular weight polymer liquids are well known viscoelastic materials. Does this viscoelasticity affect the frictional properties against a solid wall? The question is of great practical importance (as in extrusion or in injection moulding for example), but the answer is not obvious and has long remained a matter for debate. in this review, the recently developed experimental techniques that have allowed the direct measurement of the local velocity at the wall are described These techniques have demonstrated the importance of polymer molecules attached to the surface for the appearance of slip boundary conditions, that is, non-zero flow velocity at the wall. Molecular models, which describe how both the deformability of these surface chains and their degree of interdigitation with the bulk polymer are the important quantities that drive the amount of slip at the wall, will also be discussed. These ideas should lead in the near future to the design of surfaces with optimized friction properties.
BibTeX:
@article{Leger1997,
author = {Leger, L. and Hervet, H. and Massey, G.},
title = {The role of attached polymer molecules in wall slip},
journal = {Trends In Polymer Science},
year = {1997},
volume = {5},
number = {2},
pages = {40--45}
}
      
Leger, L., Hervet, H., Massey, G. & Durliat, E. Wall slip in polymer melts 1997 Journal Of Physics-Condensed Matter   article
Abstract: We present a review of the recent characterizations of the Bow behaviour of high-molecular-weight polymer melts, with special emphasis on situations in which slip at the wall appears. These characterizations are based on direct measurements of the local velocity of the fluid, in the immediate vicinity of the solid wall, through near-field velocimetry techniques. The results demonstrate the importance of polymer molecules anchored on the solid surface, either by strong adsorption or by chemical grafting, and entangled with the bulk polymer, to produce a strong friction at low shear rates and to lead to a shear rate threshold above which strong slip at the wall and low friction develop. The evolution of the shear rate threshold and of the flow characteristics (the length of the extrapolation of the velocity profile to zero, the critical slip velocity for the onset of strong slip,...) with the molecular parameters of the system (the molecular weights of the bulk and surface chains, and the surface density of anchored chains) is analysed and compared with the predictions of recent theoretical models.
BibTeX:
@article{Leger1997b,
author = {Leger, L. and Hervet, H. and Massey, G. and Durliat, E.},
title = {Wall slip in polymer melts},
journal = {Journal Of Physics-Condensed Matter},
year = {1997},
volume = {9},
number = {37},
pages = {7719--7740}
}
      
Boucher, E., Folkers, J. P., Hervet, H., Leger, L. & Creton, C. Effects of the formation of copolymer on the interfacial adhesion between semicrystalline polymers 1996 Macromolecules   article
Abstract: The relationship between the fracture toughness (G(c)) and the areal density of diblock copolymer at the interface (Sigma) was investigated for joints between polypropylene (PP) and polyamide-6 (PA6), two incompatible, semicrystalline polymers. Diblock copolymers were formed in situ by reaction between succinic acid groups terminally grafted onto 5% of the PP chains and the NH2 ends of the PA6 chains. Fracture toughnesses were measured using an asymmetric double cantilever beam test (ADCB). After the bulk PA6 had been completely rinsed from an adhered sample, X-ray photoelectron spectroscopy (XPS) was used to measure the areal density of copolymer at the interface. Above the melt temperature of PP, but below that of PA6, reaction at the interface was limited by diffusion of the reactive PP chains (D = 1.58 x 10(-11) cm(2) s(-1) at 213 degrees C). By controlling the temperature and the time of formation, G(c) could be varied in the range from 5 to 100 J/m(2). Dissipation during fracture was observed to occur by plastic deformation in the PP, and failure of the joint was determined to occur by chain scission of the PP part of the copolymer. The fracture toughness was found to vary as the square of the areal density of copolymer at the interface, a relationship similar to that observed and predicted for glassy polymers. This scaling behavior suggests that the stresses in the fracture are concentrated over a distance on the order of 10 nm at the head of the crack.
BibTeX:
@article{Boucher1996,
author = {Boucher, E. and Folkers, J. P. and Hervet, H. and Leger, L. and Creton, C.},
title = {Effects of the formation of copolymer on the interfacial adhesion between semicrystalline polymers},
journal = {Macromolecules},
year = {1996},
volume = {29},
number = {2},
pages = {774--782}
}
      
Deruelle, M., Leger, L. & TirellL, M. Adhesion At The Solid-Elastomer Interface - Influence Of The Interfacial Chains 1995 Macromolecules   article
Abstract: We have studied the adhesion between an elastomeric lens of cross-linked poly(dimethylsiloxane) (PDMS) brought into contact with a silicon wafer covered by a grafted layer of monodisperse PDMS. The influence on the adhesion of the molecular weight and the surface density of the grafted chains was examined by modifying them independently. The mechanical test we used was the JKR method, which measures the variation of the radius of the contact area, a, between the wafer and the lens as a function of P, the load applied. This technique gives the dependence of the interfacial adhesion energy, or strain energy release rate, G, on the crack propagation speed, V. We modified the apparatus commonly used to operate at constant, imposed displacement in an effort to obtain data at the lowest possible loads and deformations. Recording of a and P as a function of time enabled the determination of G as a function of V down to speeds as low as 5 nm/s. Our results show that G still depends on V, even in the lowest range of speeds. If we refer to the low-velocity values of strain energy release rate as adhesion energies, G(0), we find that G(0) is affected strongly by the grafted layer and apparently governed by the ability of the chains from the grafted layer to penetrate the network. The adhesion energies we measure are invariably higher than that expected from accounting for only the surface energy of PDMS. Layers grafted from the melt state over a range of molecular weights, where the grafted chains have their unperturbed dimensions, show less adhesion enhancement than do layers of the same thickness produced by grafting high molecular weight polymers from a range of solution concentrations, which results in compressed configurations of the grafted chains when the solution grafted layers are dried. There appears to be a thickness for the grafted layers which is optimum in generating adhesion enhancement between the lens and the wafer. By modifying the nature of the network, we have shown that the structure of the elastomer plays an important role in determining the adhesion energy.
BibTeX:
@article{DERUELLE1995,
author = {Deruelle, M. and Leger, L. and TirellL, M.},
title = {Adhesion At The Solid-Elastomer Interface - Influence Of The Interfacial Chains},
journal = {Macromolecules},
year = {1995},
volume = {28},
number = {22},
pages = {7419--7428}
}
      
Leger, L., Hervet, H., Marciano, Y., Deruelle, M. & Massey, G. Role Of Surface-Anchored Polymer-Chains In Adhesion And Slippage 1995 Israel Journal Of Chemistry   article
Abstract: When in contact with an attractive wall, polymer chains tend to form thick, surface-anchored layers with an internal structure which can be controlled. We present and analyze experiments conducted on model systems aimed at understanding how such surface-anchored polymer layers can act as adhesion promoters or can induce wall slip. For both situations, the key parameter is the degree of interdigitation between the surface layer and the bulk polymer system, either an elastomer or a melt. We analyze how this degree of interdigitation governs the optimum enhancement in the adhesion energy between the solid wall and an elastomer, and how it is at the origin of the very different wall slip regimes observed experimentally.
BibTeX:
@article{LEGER1995,
author = {Leger, L. and Hervet, H. and Marciano, Y. and Deruelle, M. and Massey, G.},
title = {Role Of Surface-Anchored Polymer-Chains In Adhesion And Slippage},
journal = {Israel Journal Of Chemistry},
year = {1995},
volume = {35},
number = {1},
pages = {65--74}
}
      
Leger, L., Hervet, H. & Massey, G. Role Of Polymer-Molecules Attached To The Surface On Wall Slip 1995 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{LEGER1995a,
author = {Leger, L. and Hervet, H. and Massey, G.},
title = {Role Of Polymer-Molecules Attached To The Surface On Wall Slip},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1995},
volume = {209},
pages = {9--POLY}
}
      
Mann, E. K., Henon, S., D., L., Meunier, J. & Leger, L. Hydrodynamics Of Domain Relaxation In A Polymer Monolayer 1995 Physical Review E   article
BibTeX:
@article{MANN1995,
author = {Mann, E. K. and Henon, S. and Langevin D. and Meunier, J. and Leger, L.},
title = {Hydrodynamics Of Domain Relaxation In A Polymer Monolayer},
journal = {Physical Review E},
year = {1995},
volume = {51},
number = {6},
pages = {5708--5720}
}
      
Boucher, E., Folkers, J. P., Hervet, H. & Leger, L. Adhesion Between Semicrystalline Polymers 1994 Vide-Science Technique Et Applications   article
Abstract: The energy of adhesion between two incompatible, semicrystalline polymers polypropylene (PP) and polyamide 6 (PA6) - has been measured using the double cantilever beam (DCB) test. Junctions between the polymers were formed by chemical reaction between NH2 ends of the PA6 and succinic acid groups on a small percentage of PP chains. The results presented here show that the DCB test is a reliable tool for measuring energies of adhesion between semicrystalline polymers in the range of one to several hundred joules per square meter. X-ray photoelectron spectroscopy and scanning electron microscopy were used to elucidate the mechanism of adhesion. These results show that chain pull-out occurs from the polypropylene over the explored range of energies, and that crazing probably also occurs at high energies.
BibTeX:
@article{BOUCHER1994,
author = {Boucher, E. and Folkers, J. P. and Hervet, H. and Leger, L.},
title = {Adhesion Between Semicrystalline Polymers},
journal = {Vide-Science Technique Et Applications},
year = {1994},
number = {272},
pages = {442--445}
}
      
Brochard-Wyart, F., de Gennes, P., Leger, L., Marciano, Y. & Rapha�l, E. Adhesion Promoters 1994 Journal Of Physical Chemistry   article
Abstract: Adhesion between a flat solid and a rubber is considerably increased by grafting chains (chemically identical to the rubber) on the solid surface. Similarly, a population of mobile chains dissolved into rubber can increase the strength of a rubber/rubber contact. A third (more recent) type of promoter is a ''Guiselin brush'', obtained by incubating certain polymer melts against a suitable solid. A major practical problem is to understand how the adhesive energy varies with the surface concentration sigma of ''connector molecules'': very often, at high connector density, the strength goes down. We set up a theoretical picture of polymer interdigitation, covering most of the cases listed above. We also describe peeling measurements of the adhesion energy G(sigma) for Guiselin brushes (silica/PDMS/PDMS network). For the Guiselin brush, the statistical problem is much more complex. The main experimental result is the presence of a clear maximum in the plot of G(sigma).
BibTeX:
@article{BROCHARDWYART1994,
author = {Brochard-Wyart, F. and de Gennes, P.-G. and Leger, L. and Marciano, Y. and Rapha�l, E.},
title = {Adhesion Promoters},
journal = {Journal Of Physical Chemistry},
year = {1994},
volume = {98},
number = {38},
pages = {9405--9410}
}
      
Deruelle, M., Tirell, M., Marciano, Y., Hervet, H. & �ger, L. Adhesion Energy Between Polymer Networks And Solid-Surfaces Modified By Polymer Attachment 1994 Faraday Discussions   article
Abstract: The adhesion energy, or strain energy release rate, G, between polydimethylsiloxane (PDMS) elastomers and flat silica surfaces modified by irreversible adsorption and end grafting of PDMS chains, has been characterised through peel tests and 'JKR' experiments. The 90 degrees peel tests have been conducted down to very low velocity (5 nm s(-1)). In the 'JKR' experiment, a small spherical cap of elastomer is pushed against the surface, and the area of contact is monitored as a function of the applied load, allowing the determination of both G and the elastic modulus of the elastomer, E. Systematic measurements have been made, varying the molecular architecture of both the elastomer and the grafted layer (chain length and surface chain density). Our central result is that G, measured at the lowest possible accessible rates, passes through a maximum when the surface density of grafted chains increases. This can be rationalised in the framework of recent models of polymer-polymer junctions, provided that the ability of the grafted chains to penetrate into the network is accounted for. When the velocity of the advancing fracture is increased, the measured adhesion energy increases strongly and non-linearly, contrary to the predictions of molecular models based on the suction mechanism.
BibTeX:
@article{DERUELLE1994,
author = {Deruelle, M. and Tirell, M. and Marciano, Y. and Hervet, H. and �ger, L.},
title = {Adhesion Energy Between Polymer Networks And Solid-Surfaces Modified By Polymer Attachment},
journal = {Faraday Discussions},
year = {1994},
pages = {55--65}
}
      
Elkissi, N., Leger, L., Piau, J. & Mezghani, A. Effect Of Surface-Properties On Polymer Melt Slip And Extrusion Defects 1994 Journal Of Non-Newtonian Fluid Mechanics   article
Abstract: The purpose of this study is to analyse the flow of a linear polydimethylsiloxane of high molecular weight on plane surfaces that may interact differently with the silicone fluid used. Stainless steel surfaces and slightly rough silicon surfaces were examined, including silica surfaces where monolayers of fluorine chains were grafted on by silanation reactions. The interest and principle of these reactions are briefly recalled. The quality of the surface treatment was checked by wetting experiments. For each ''fluid-wall material'' pair, flow rate measurements were performed under a given pressure. In addition, the extrudate was photographed under various flow regimes. Combined analysis of the flow curves and observations at the die outlet helped to determine the effect of roughness and of the wall material for the specific flow conditions considered.
BibTeX:
@article{ELKISSI1994,
author = {Elkissi, N. and Leger, L. and Piau, J.-M. and Mezghani, A.},
title = {Effect Of Surface-Properties On Polymer Melt Slip And Extrusion Defects},
journal = {Journal Of Non-Newtonian Fluid Mechanics},
year = {1994},
volume = {52},
number = {2},
pages = {249--261}
}
      
Migler, K. B., Massey, G., Hervet, H. & Leger, L. The Slip Transition At The Polymer Solid Interface 1994 Journal Of Physics-Condensed Matter   article
Abstract: Direct measurements of the velocity of a high-molecular-weight polydimethylsiloxane melt in the immediate vicinity of a solid wall (100 nm from the interface) have been conducted, using a novel optical technique based on evanescent wave induced fluorescence and pattern photobleaching. On silica, quite distinct behaviours are observed: (i) for weak polymer-surface interactions (silica modified by grafting of C18 hydrocarbon chains), a sharp transition between almost no and strong slippage at the wall appears for high enough shear rate, in good agreement with a recent model that ascribes the onset of slippage to a stretching transition of a few chains attached to the surface; (ii) for strong polymer-surface interactions (bare silica) chains irreversibly adsorbed build a pseudo-brush; only weak slippage develops with b (the length under the surface where the velocity extrapolates to zero) independent of the shear rate. No sharp transition appears within the explored shear rate range.
BibTeX:
@article{MIGLER1994,
author = {Migler, K. B. and Massey, G. and Hervet, H. and Leger, L.},
title = {The Slip Transition At The Polymer Solid Interface},
journal = {Journal Of Physics-Condensed Matter},
year = {1994},
volume = {6},
pages = {A301--A304}
}
      
Leger, L. Polymer-Solid Adhesion - Experiments And Recent Models 1993 Vide-Science Technique Et Applications   article
BibTeX:
@article{LEGER1993,
author = {Leger, L.},
title = {Polymer-Solid Adhesion - Experiments And Recent Models},
journal = {Vide-Science Technique Et Applications},
year = {1993},
volume = {49},
number = {268},
pages = {295--302}
}
      
Leger, L. Polymer-Solid Adhesion - Experiences And Recent Models 1993 Vide-Science Technique Et Applications   article
Abstract: After a brief overview of the recent models developped by P.G. de GENNES and coworkers in order to relate adhesion performances of polymers to their molecular organisation, the results of series of experiments conducted on model systems will be presented and discussed. A particular emphasis will be put on weak adhesive junctions in which a small number of polymer chains bound to the solid surface are responsible of a strong adhesion, even if they are not chemically attached to the bulk polymer, as they provide an efficient way of dissipating energy through an extraction mechanism when one brakes the adhesive joint.
BibTeX:
@article{LEGER1993a,
author = {Leger, L.},
title = {Polymer-Solid Adhesion - Experiences And Recent Models},
journal = {Vide-Science Technique Et Applications},
year = {1993},
number = {268},
pages = {92--99}
}
      
Marzolin, C., Hervet, H. & Leger, L. Direct Experimental Tests Of The Interpenetration Of A Grafted Polymer Brush With A Solution Or A Melt 1993 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{MARZOLIN1993,
author = {Marzolin, C. and Hervet, H. and Leger, L.},
title = {Direct Experimental Tests Of The Interpenetration Of A Grafted Polymer Brush With A Solution Or A Melt},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1993},
volume = {206},
pages = {22--MACR}
}
      
Migler, K. B., Hervet, H. & Leger, L. Slip Transition Of A Polymer Melt Under Shear-Stress 1993 Physical Review Letters   article
Abstract: We present the first direct measurements of the local velocity of a sheared polymer melt within the first 100 nm from the solid-liquid interface. For high enough shear rates we observe a sharp transition between weak and strong slip (i.e., a nonzero boundary fluid velocity) in the case of weak polymer-surface interactions [polydimethylsiloxane (PDMS) on silanated silica surfaces]. For strong polymer-surface interactions the slip is strongly reduced. These results are compared to a theoretical model recently proposed by Brochard and de Gennes.
BibTeX:
@article{MIGLER1993,
author = {Migler, K. B. and Hervet, H. and Leger, L.},
title = {Slip Transition Of A Polymer Melt Under Shear-Stress},
journal = {Physical Review Letters},
year = {1993},
volume = {70},
number = {3},
pages = {287--290}
}
      
Auroy, P., Auvray, L. & Leger, L. Silica Particles Stabilized By Long Grafted Polymer-Chains - From Electrostatic To Steric Repulsion 1992 Journal Of Colloid And Interface Science   article
BibTeX:
@article{AUROY1992,
author = {Auroy, P. and Auvray, L. and Leger, L.},
title = {Silica Particles Stabilized By Long Grafted Polymer-Chains - From Electrostatic To Steric Repulsion},
journal = {Journal Of Colloid And Interface Science},
year = {1992},
volume = {150},
number = {1},
pages = {187--194}
}
      
Dvolaitzky, M., Guedeau Boudeville, M. & Leger, L. Polymerization-Induced Shrinkage In Giant Butadienic Lipid Vesicles 1992 Langmuir   article
Abstract: A new butadienic lipid, dimethylbis[2(tetradeca-2,4-dienoyl)oxyethyl]ammonium bromide, has been used to form giant vesicles. Under UV irradiation, a spectacular change in the morphology of these vesicles is observed: a global shrinkage, along with a thickening or crumpling of the membrane (depending upon the conditions of irradiation). The kinetics of the shrinkage are totally different (much slower) than those of the polymerization (monitored by the disappearance of the absorption due to the conjugated double bonds of the diene at 262 nm). This is indicative of a two-step process: the shrinkage resulting from rapid polymerization followed by slow expulsion of part of the water inside the vesicles.
BibTeX:
@article{DVOLAITZKY1992,
author = {Dvolaitzky, M. and Guedeau Boudeville, M.-A. and Leger, L.},
title = {Polymerization-Induced Shrinkage In Giant Butadienic Lipid Vesicles},
journal = {Langmuir},
year = {1992},
volume = {8},
number = {11},
pages = {2595--2597}
}
      
Leger, L. & Joanny, J. F. Liquid Spreading 1992 Reports On Progress In Physics   article
Abstract: We review the wetting and spreading properties of simple liquids on solid surfaces, putting emphasis on the role of the heterogeneities of the solid surface and on the spreading kinetics. In a situation of partial wetting, the liquid does not spread completely and shows a finite contact angle on a solid surface. The partial wetting behaviour on perfect solid surfaces is well described by classical capillarity. Heterogeneities of the solid surface lead to contact angle hysteresis. In a complete wetting situation, the liquid forms a film on a solid surface with a thickness in the mesoscopic range. The direct long range interaction between liquid and solid described by the so-called disjoining pressure governs the physics of these films. Films of mesoscopic thickness also appear in the spreading kinetics of liquids. These precursor films form ahead of macroscopic advancing liquid fronts. The spreading kinetics is extremely slow.
BibTeX:
@article{LEGER1992,
author = {Leger, L. and Joanny, J. F.},
title = {Liquid Spreading},
journal = {Reports On Progress In Physics},
year = {1992},
volume = {55},
number = {4},
pages = {431--486}
}
      
Silberzan, P. & Leger, L. Spreading Of High-Molecular-Weight Polymer Melts On High-Energy Surfaces 1992 Macromolecules   article
Abstract: The spreading behavior of high molecular weight poly(dimethylsiloxane) (PDMS) drops on silica surfaces has been investigated through optical microscopy and ellipsometry. For molecular weights higher than the entanglement molecular weight, both the drop profile and the macroscopic spreading kinetics differ from the well-known low molecular weight behavior: a "bump" appears on the side of the macroscopic drop at thicknesses comparable to the radius of gyration of the chains while the macroscopic spreading slows down and finally stops, departing from the usually observed Tanner's law. The existence of the bump is highly sensitive to the nature of the monomer-substrate interactions. The lateral extension of the bump evolves with time in a diffusive manner, and the molecular weight dependence of the corresponding diffusion coefficient appears compatible with a reptation process for the transport of the chains along the surface. These results will be discussed and compared to recent theoretical predictions which take into account two characteristic features of the hydrodynamics of entangled polymer melts, namely, a finite slippage of the chains at the solid wall and an enhanced friction of the monomers in contact with the surface due to solid-monomer interactions.
BibTeX:
@article{SILBERZAN1992,
author = {Silberzan, P. and Leger, L.},
title = {Spreading Of High-Molecular-Weight Polymer Melts On High-Energy Surfaces},
journal = {Macromolecules},
year = {1992},
volume = {25},
number = {4},
pages = {1267--1271}
}
      
Auroy, P., Auvray, L. & Leger, L. Characterization Of The Brush Regime For Grafted Polymer Layers At The Solid-Liquid Interface 1991 Physical Review Letters   article
Abstract: Using small-angle neutron-scattering techniques, the scaling laws between the thickness of a grafted polymer layer h, its graft density sigma, and the molecular weight of the grafted chains M have been determined for polydimethylsiloxane chains end grafted on porous silica. The observed laws h almost-equal-to M-sigma in bad solvent and h almost-equal-to M-sigma-1/3 in good solvent provide the first experimental evidence of the "brush" regime, where the grafted chains, confined by their neighbors, are stretched normal to the surface.
BibTeX:
@article{AUROY1991,
author = {Auroy, P. and Auvray, L. and Leger, L.},
title = {Characterization Of The Brush Regime For Grafted Polymer Layers At The Solid-Liquid Interface},
journal = {Physical Review Letters},
year = {1991},
volume = {66},
number = {6},
pages = {719--722}
}
      
Auroy, P., Auvray, L. & Leger, L. The Scattering By Grafted Polymers 1991 Physica A   article
Abstract: We have used small angle neutron scattering and the method of contrast variation to study the structure of layers of poly(dimethylsiloxane) terminally grafted on porous silica. We review the main results that we have obtained by varying the polymer molecular weight, the grafting density and the solvent quality. The grafting density depends mainly on the concentration in the reaction bath. At high grafting density and in a good solvent, the chains are stretched and have the same local structure as in bulk semi-dilute solutions of equivalent concentration; furthermore the thickness of the layers is proportional to the polymer molecular weight as predicted by S. Alexander more than ten years ago.
BibTeX:
@article{AUROY1991a,
author = {Auroy, P. and Auvray, L. and Leger, L.},
title = {The Scattering By Grafted Polymers},
journal = {Physica A},
year = {1991},
volume = {172},
number = {1-2},
pages = {269--284}
}
      
Auroy, P., Auvray, L. & Leger, L. Structures Of End-Grafted Polymer Layers - A Small-Angle Neutron-Scattering Study 1991 Macromolecules   article
Abstract: The structures of grafted poly(dimethylsiloxane) layers at the solid-liquid interface, in the regime of high graft density, have been investigated in various solvents, using small-angle neutron scattering techniques. In a poor solvent, the grafted polymer layer is dense with two well-defined boundaries, leading to interference phenomena. In a good solvent, the chains are stretched and exhibit the same behavior as in semidilute solution. Although the average interfacial density profile is smoother than a step function, the "brush" model is in good agreement with our observations.
BibTeX:
@article{AUROY1991b,
author = {Auroy, P. and Auvray, L. and Leger, L.},
title = {Structures Of End-Grafted Polymer Layers - A Small-Angle Neutron-Scattering Study},
journal = {Macromolecules},
year = {1991},
volume = {24},
number = {9},
pages = {2523--2528}
}
      
Auroy, P., Auvray, L. & Leger, L. Building Of A Grafted Layer .1. Role Of The Concentration Of Free Polymers In The Reaction Bath 1991 Macromolecules   article
Abstract: Using small angle neutron scattering techniques, we have studied the formation of layers of poly(dimethylsiloxane) chains grafted on nonadsorbing silica. The grafting density is uniquely determined by the concentration of free polymers in the reaction bath C(b) and it increases like c(b)7/8 provided that C(b) is greater than the overlap threshold. When the grafted layers are immersed in pure solvents, they exhibit different conformations, driven by the solvent quality and the grafting density. In poor solvent, at wide spacing D, the chains spread on the silica surface, forming two-dimensional films. When D becomes smaller, the grafted layer becomes thicker and more regular. In good solvent, at large D, the chains form juxtaposed mushrooms, without interactions. Below a threshold D*, they stretch themselves, yielding polymer brushes. At very high grafting density, saturation of the stretching occurs, which could be due to curvature effect or to the finite extensibility of the chains.
BibTeX:
@article{AUROY1991c,
author = {Auroy, P. and Auvray, L. and Leger, L.},
title = {Building Of A Grafted Layer .1. Role Of The Concentration Of Free Polymers In The Reaction Bath},
journal = {Macromolecules},
year = {1991},
volume = {24},
number = {18},
pages = {5158--5166}
}
      
Silberzan, P. & Leger, L. Spreading Of Polymer Microdrops On High-Energy Solid-Surfaces 1991 Comptes Rendus De L Academie Des Sciences Serie Ii   article
Abstract: We present an experimental investigation of the spreading of high molecular weight polymer droplets on high-energy silica surfaces. The spreading kinetics of the macroscopic part of the drop deviates from Tanner's laws, while a bump develops in the drop profile at thicknesses comparable to the radius of gyration of the chains. The lateral extension of this bump increases with time in a diffusive way.
BibTeX:
@article{SILBERZAN1991,
author = {Silberzan, P. and Leger, L.},
title = {Spreading Of Polymer Microdrops On High-Energy Solid-Surfaces},
journal = {Comptes Rendus De L Academie Des Sciences Serie Ii},
year = {1991},
volume = {312},
number = {10},
pages = {1089--1094}
}
      
Silberzan, P. & Leger, L. Evidence For A New Spreading Regime Between Partial And Total Wetting 1991 Physical Review Letters   article
Abstract: We present an investigation of the macroscopic spreading behavior of polydimethylsiloxane droplets on solid surfaces of adjustable spreading power. This is obtained through chemical grafting of mixed self-assembled monolayers on silicon wafers. Between partial wetting and high-energy-type total wetting, we identify for the first time a new regime in which the whole spreading kinetics is highly sensitive to the layer polarizability. This new regime can be interpreted in terms of oscillating van der Waals interactions, and identified with the pseudo partial wetting recently predicted.
BibTeX:
@article{SILBERZAN1991b,
author = {Silberzan, P. and Leger, L.},
title = {Evidence For A New Spreading Regime Between Partial And Total Wetting},
journal = {Physical Review Letters},
year = {1991},
volume = {66},
number = {2},
pages = {185--188}
}
      
Silberzan, P., Leger, L., Ausserre, D. & Benattar, J. J. Silanation Of Silica Surfaces - A New Method Of Constructing Pure Or Mixed Monolayers 1991 Langmuir   article
Abstract: We present a quantitative study of different parameters of the silanation reaction (grafting of long aliphatic chains on silica surfaces via trichlorosilane group). Some of them, such as temperature or water traces, are shown to be particularly crucial. A mechanism for the reaction, completing the one previously reported, is proposed and optimal experimental conditions to perform high-quality monolayers of long aliphatic chains are deduced. Characterizations were performed with different techniques including X-ray reflectivity experiments and contact angle measurements. Results are consistent with well organized layers in which the chains are densely packed completely extended perpendicular to the surface. In the case of mixtures, the layer comportment reflects the concentration of each species in solution; there does not seem to be any segregation.
BibTeX:
@article{SILBERZAN1991a,
author = {Silberzan, P. and Leger, L. and Ausserre, D. and Benattar, J. J.},
title = {Silanation Of Silica Surfaces - A New Method Of Constructing Pure Or Mixed Monolayers},
journal = {Langmuir},
year = {1991},
volume = {7},
number = {8},
pages = {1647--1651}
}
      
Auroy, P., Auvray, L. & Leger, L. The Study Of Grafted Polymer Layers By Neutron-Scattering 1990 Journal Of Physics-Condensed Matter   article
Abstract: The structure of layers of poly(dimethylsiloxane) terminally grafted on silica has been studied by small angle neutron scattering. We have observed the influence of the polymer molecular weight, the grafting density and the solvent quality. At a high grafting density, in good and in bad solvents, the chains are stretched and the thickness of the layers is proportional to the polymer mass. In a good solvent the inner structure of the layers is similar to that of a semi-dilute solution of free polymer at the same local concentration, in agreement with the description of Alexander.
BibTeX:
@article{AUROY1990,
author = {Auroy, P. and Auvray, L. and Leger, L.},
title = {The Study Of Grafted Polymer Layers By Neutron-Scattering},
journal = {Journal Of Physics-Condensed Matter},
year = {1990},
volume = {2},
pages = {SA317--SA321}
}
      
Daillant, J., Benattar, J. J. & Leger, L. Ultrathin Films In Wetting Evidenced By X-Ray Reflectivity 1990 Physical Review A   article
BibTeX:
@article{DAILLANT1990,
author = {Daillant, J. and Benattar, J. J. and Leger, L.},
title = {Ultrathin Films In Wetting Evidenced By X-Ray Reflectivity},
journal = {Physical Review A},
year = {1990},
volume = {41},
number = {4},
pages = {1963--1977}
}
      
Leger, L. & Benattar, J. J. From Drop To Pancake - Wetting Observed With X-Rays 1990 Recherche   article
BibTeX:
@article{LEGER1990,
author = {Leger, L. and Benattar, J. J.},
title = {From Drop To Pancake - Wetting Observed With X-Rays},
journal = {Recherche},
year = {1990},
volume = {21},
number = {217},
pages = {88--90}
}
      
Leger, L. & Silberzan, P. The Spreading Of Drops On Solid-Surfaces 1990 Journal Of Physics-Condensed Matter   article
Abstract: We present a detailed study of the macroscopic spreading kinetics of a non-volatile liquid, polydimethylsiloxane, on model solid surfaces of continuously adjustable spreading power, with special attention paid to the immediate vicinity of the zero spreading parameter value. We establish the existence of new spreading regimes which are, we think, the signature of non-monotonic interactions versus thickness laws.
BibTeX:
@article{LEGER1990b,
author = {Leger, L. and Silberzan, P.},
title = {The Spreading Of Drops On Solid-Surfaces},
journal = {Journal Of Physics-Condensed Matter},
year = {1990},
volume = {2},
pages = {SA421--SA425}
}
      
Leger, L., Silberzan, P., Erman, M., Daillant, J. & Benattar, J. J. Spreading Of Polymer Liquids On Solid-Surfaces - Light And X-Rays Reflectivity Investigations 1990 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{LEGER1990a,
author = {Leger, L. and Silberzan, P. and Erman, M. and Daillant, J. and Benattar, J. J.},
title = {Spreading Of Polymer Liquids On Solid-Surfaces - Light And X-Rays Reflectivity Investigations},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1990},
volume = {200},
pages = {106--POLY}
}
      
Auroy, P., Hervet, H. & Leger, L. Dynamic Properties Of A Semi-Flexible Polymer 1989 Polymer Communications   article
BibTeX:
@article{AUROY1989,
author = {Auroy, P. and Hervet, H. and Leger, L.},
title = {Dynamic Properties Of A Semi-Flexible Polymer},
journal = {Polymer Communications},
year = {1989},
volume = {30},
number = {9},
pages = {272--274}
}
      
Benattar, J. J., Daillant, J., Bosio, L. & Leger, L. Physical-Properties Of Ultra Thin-Films Studied By X-Ray Optical Techniques - Langmuir-Blodgett Multilayer Structures, Organic Monolayers On Water And The Spreading Of Polymer Micro-Droplets 1989 Journal De Physique   article
BibTeX:
@article{BENATTAR1989,
author = {Benattar, J. J. and Daillant, J. and Bosio, L. and Leger, L.},
title = {Physical-Properties Of Ultra Thin-Films Studied By X-Ray Optical Techniques - Langmuir-Blodgett Multilayer Structures, Organic Monolayers On Water And The Spreading Of Polymer Micro-Droplets},
journal = {Journal De Physique},
year = {1989},
volume = {50},
number = {C7},
pages = {C739--C766}
}
      
Leger, L., Silberzan, P. & Erman, M. Spreading Of Polymer Liquids On Solid-Surfaces - Effect Of Chain Confinement On The Kinetics And The Precursor Film Profiles 1989 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{LEGER1989,
author = {Leger, L. and Silberzan, P. and Erman, M.},
title = {Spreading Of Polymer Liquids On Solid-Surfaces - Effect Of Chain Confinement On The Kinetics And The Precursor Film Profiles},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1989},
volume = {197},
pages = {260--POLY}
}
      
Daillant, J., Benattar, J. J., Bosio, L. & Leger, L. Final Stages Of Spreading Of Polymer Droplets On Smooth Solid-Surfaces 1988 Europhysics Letters   article
BibTeX:
@article{DAILLANT1988,
author = {Daillant, J. and Benattar, J. J. and Bosio, L. and Leger, L.},
title = {Final Stages Of Spreading Of Polymer Droplets On Smooth Solid-Surfaces},
journal = {Europhysics Letters},
year = {1988},
volume = {6},
number = {5},
pages = {431--436}
}
      
Leger, L. Self-Diffusion In Entangled Polymer Systems - Characterization Of The Different Dynamic Regimes, Reptation And Others 1988 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{LEGER1988b,
author = {Leger, L.},
title = {Self-Diffusion In Entangled Polymer Systems - Characterization Of The Different Dynamic Regimes, Reptation And Others},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1988},
volume = {195},
pages = {273--POLY}
}
      
Leger, L., Erman, M., Guinet-Picard, A. M., Ausserre, D. & Strazielle, C. Precursor Film Profiles Of Spreading Liquid-Drops 1988 Physical Review Letters   article
BibTeX:
@article{LEGER1988,
author = {Leger, L. and Erman, M. and Guinet-Picard, A. M. and Ausserre, D. and Strazielle, C.},
title = {Precursor Film Profiles Of Spreading Liquid-Drops},
journal = {Physical Review Letters},
year = {1988},
volume = {60},
number = {23},
pages = {2390--2393}
}
      
Leger, L., Erman, M., Guinet-Picart, A. M., Ausserre, D., Strazielle, C., Benattar, J. J., Rieutord, F., Daillant, J. & Bosio, L. Spreading Of Non Volatile Liquids On Smooth Solid-Surfaces - Role Of Long-Range Forces 1988 Revue De Physique Appliquee   article
BibTeX:
@article{LEGER1988a,
author = {Leger, L. and Erman, M. and Guinet-Picart, A. M. and Ausserre, D. and Strazielle, C. and Benattar, J. J. and Rieutord, F. and Daillant, J. and Bosio, L.},
title = {Spreading Of Non Volatile Liquids On Smooth Solid-Surfaces - Role Of Long-Range Forces},
journal = {Revue De Physique Appliquee},
year = {1988},
volume = {23},
number = {6},
pages = {1047--1054}
}
      
Leger, L., Guinet-Picard, A. M., Hervet, H., Ausserre, D., Erman, M., BROCHARD, F. & Joanny, J. F. Dry Spreading Of Polymer Liquids On Solid-Surfaces - Role Of Long-Range Forces, Precursor Film Profiles And Specific Polymeric Effects 1988 Abstracts Of Papers Of The American Chemical Society   article
BibTeX:
@article{LEGER1988c,
author = {Leger, L. and Guinet-Picard, A. M. and Hervet, H. and Ausserre, D. and Erman, M. and BROCHARD, F. and Joanny, J. F.},
title = {Dry Spreading Of Polymer Liquids On Solid-Surfaces - Role Of Long-Range Forces, Precursor Film Profiles And Specific Polymeric Effects},
journal = {Abstracts Of Papers Of The American Chemical Society},
year = {1988},
volume = {195},
pages = {222--POLY}
}
      
Leger, L. & Viovy, J. L. Entangled Polymers 1988 Contemporary Physics   article
BibTeX:
@article{LEGER1988d,
author = {Leger, L. and Viovy, J. L.},
title = {Entangled Polymers},
journal = {Contemporary Physics},
year = {1988},
volume = {29},
number = {6},
pages = {579--595}
}
      
Fabre, P., Leger, L. & Veyssie, M. Reverse Anisotropy Of The Diffusion-Coefficients In A Polymeric Nematic Medium 1987 Physical Review Letters   article
BibTeX:
@article{FABRE1987,
author = {Fabre, P. and Leger, L. and Veyssie, M.},
title = {Reverse Anisotropy Of The Diffusion-Coefficients In A Polymeric Nematic Medium},
journal = {Physical Review Letters},
year = {1987},
volume = {59},
number = {2},
pages = {210--212}
}
      
Guillot, G., Leger, L. & Rondelez, F. Polymers That Slip Away 1987 Recherche   article
BibTeX:
@article{GUILLOT1987,
author = {Guillot, G. and Leger, L. and Rondelez, F.},
title = {Polymers That Slip Away},
journal = {Recherche},
year = {1987},
volume = {18},
number = {191},
pages = {1126--1128}
}
      
Leger, L. Wetting And Polymer Diffusion - Application To Adhesive Bonding 1987 Annales De Chimie-Science Des Materiaux   article
BibTeX:
@article{LEGER1987,
author = {Leger, L.},
title = {Wetting And Polymer Diffusion - Application To Adhesive Bonding},
journal = {Annales De Chimie-Science Des Materiaux},
year = {1987},
volume = {12},
number = {2},
pages = {175--184}
}
      
Leger, L. Wetting - Role Of Long-Range Forces 1987 Vide-Science Technique Et Applications   article
BibTeX:
@article{LEGER1987a,
author = {Leger, L.},
title = {Wetting - Role Of Long-Range Forces},
journal = {Vide-Science Technique Et Applications},
year = {1987},
volume = {42},
number = {238},
pages = {403--408}
}
      
Licinio, P., Delaye, M., Livesey, A. K. & Leger, L. Colloidal Dispersions Of Alpha-Crystallin Proteins .2. Dynamics - A Maximum-Entropy Analysis Of Photon-Correlation Spectroscopy Data 1987 Journal De Physique   article
BibTeX:
@article{LICINIO1987,
author = {Licinio, P. and Delaye, M. and Livesey, A. K. and Leger, L.},
title = {Colloidal Dispersions Of Alpha-Crystallin Proteins .2. Dynamics - A Maximum-Entropy Analysis Of Photon-Correlation Spectroscopy Data},
journal = {Journal De Physique},
year = {1987},
volume = {48},
number = {7},
pages = {1217--1223}
}
      
Ausserre, D., Picard, A. M. & Leger, L. Existence And Role Of The Precursor Film In The Spreading Of Polymer Liquids 1986 Physical Review Letters   article
BibTeX:
@article{AUSSERRE1986,
author = {Ausserre, D. and Picard, A. M. and Leger, L.},
title = {Existence And Role Of The Precursor Film In The Spreading Of Polymer Liquids},
journal = {Physical Review Letters},
year = {1986},
volume = {57},
number = {21},
pages = {2671--2674}
}
      
Deschamps, H. & Leger, L. Self-Diffusion Measurements In Polymer-Solutions At The Theta-Temperature By Forced Rayleigh Light-Scattering 1986 Macromolecules   article
BibTeX:
@article{DESCHAMPS1986,
author = {Deschamps, H. and Leger, L.},
title = {Self-Diffusion Measurements In Polymer-Solutions At The Theta-Temperature By Forced Rayleigh Light-Scattering},
journal = {Macromolecules},
year = {1986},
volume = {19},
number = {11},
pages = {2760--2765}
}
      
Dimeglio, J. M., Dvolaitsky, M., Leger, L. & Taupin, C. 1st Observation Of The Undulation Mode In Birefringent Microemulsions By Quasielastic Light-Scattering 1985 Physical Review Letters   article
BibTeX:
@article{DIMEGLIO1985,
author = {Dimeglio, J. M. and Dvolaitsky, M. and Leger, L. and Taupin, C.},
title = {1st Observation Of The Undulation Mode In Birefringent Microemulsions By Quasielastic Light-Scattering},
journal = {Physical Review Letters},
year = {1985},
volume = {54},
number = {15},
pages = {1686--1689}
}
      
Guillot, G., Leger, L. & Rondelez, F. Diffusion Of Large Flexible Polymer-Chains Through Model Porous Membranes 1985 Macromolecules   article
BibTeX:
@article{GUILLOT1985,
author = {Guillot, G. and Leger, L. and Rondelez, F.},
title = {Diffusion Of Large Flexible Polymer-Chains Through Model Porous Membranes},
journal = {Macromolecules},
year = {1985},
volume = {18},
number = {12},
pages = {2531--2537}
}
      
Marmonier, M. F. & Leger, L. Reptation And Tube Renewal In Entangled Polymer-Solutions 1985 Physical Review Letters   article
BibTeX:
@article{MARMONIER1985,
author = {Marmonier, M. F. and Leger, L.},
title = {Reptation And Tube Renewal In Entangled Polymer-Solutions},
journal = {Physical Review Letters},
year = {1985},
volume = {55},
number = {10},
pages = {1078--1081}
}
      

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