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Abouhadid F, Lai VV, Morgado N, Mazuyer D, Cayer-Barrioz J. Effect of Surface Chemistry on the Squeeze-Thin Film and Friction of Boundary Films. Langmuir 2024; 40:5205-5213. [PMID: 38420687 PMCID: PMC10939031 DOI: 10.1021/acs.langmuir.3c03409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024]
Abstract
An approach combining adsorption characterization and lubricity effectiveness of amine-based friction modifier molecules has been performed using chemically controlled surfaces, coated either with cobalt or carbon, while keeping the surface roughness constant and sub-nanometric. Through squeeze measurements and numerical modeling, we have identified the mechanical properties of both adsorbed amine films, as a function of the surface on which they were formed. On the one hand, we were able to evidence that the fluid structuring at the vicinity of the adsorbed boundary film differed as a function of the latter mechanical properties, directly resulting from its molecular organization. On the other hand, we showed that the coverage ratio of the monolayer associated with the shear elastic modulus of the boundary film governed the friction level. Changing the surface chemistry while keeping the roughness constant controls the final organization in the boundary layer, the correlated mechanical properties, and the level of friction dissipation.
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Affiliation(s)
- Fadlallah Abouhadid
- Laboratoire de Tribologie
et Dynamique des Systèmes, CNRS UMR 5513, Ecole Centrale de Lyon, 36 Avenue
Guy de Collongue, Ecully Cedex 69134, France
| | - Van-Vuong Lai
- Laboratoire de Tribologie
et Dynamique des Systèmes, CNRS UMR 5513, Ecole Centrale de Lyon, 36 Avenue
Guy de Collongue, Ecully Cedex 69134, France
| | - Nazario Morgado
- Laboratoire de Tribologie
et Dynamique des Systèmes, CNRS UMR 5513, Ecole Centrale de Lyon, 36 Avenue
Guy de Collongue, Ecully Cedex 69134, France
| | - Denis Mazuyer
- Laboratoire de Tribologie
et Dynamique des Systèmes, CNRS UMR 5513, Ecole Centrale de Lyon, 36 Avenue
Guy de Collongue, Ecully Cedex 69134, France
| | - Juliette Cayer-Barrioz
- Laboratoire de Tribologie
et Dynamique des Systèmes, CNRS UMR 5513, Ecole Centrale de Lyon, 36 Avenue
Guy de Collongue, Ecully Cedex 69134, France
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Barazzutti C, Cayer-Barrioz J, Mazuyer D. Thin films in hydrodynamic lubrication regime: The Osiris friction setup. Rev Sci Instrum 2023; 94:065103. [PMID: 37862505 DOI: 10.1063/5.0155813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/29/2023] [Indexed: 10/22/2023]
Abstract
A model hydrodynamic lubrication tribometer consisting of two hydrodynamic journal bearings working under thin film conditions was developed to investigate the mechanisms of hydrodynamic friction with low-viscosity fluids and the role of surface effects. A small nominal radial clearance of about 5 µm was considered between the two surfaces. This fully instrumented setup provides in situ information on the sheared fluid film in terms of simultaneous measurements of film thickness; localization and extension of the cavitation zone, with a resolution of 30°; nominal friction torques up to 0.5 N m, with an accuracy of 0.05 mN m; temperature; and the position of the shaft for velocities up to 12 000 rpm. To illustrate the capability of the Osiris tribometer, thin hydrodynamic film measurements were performed on smooth surfaces. The results are presented here, and the thermal effects, acceleration, and inertia contributions are discussed. Finally, the influence of the surface topography using textured surfaces was demonstrated and the role of adsorbed layers on the surface due to fluid formulation was highlighted.
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Affiliation(s)
- Cedric Barazzutti
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, École Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully Cedex, France
| | - Juliette Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, École Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully Cedex, France
| | - Denis Mazuyer
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, École Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully Cedex, France
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Hopper N, Sidoroff F, Rana R, Bavisotto R, Cayer-Barrioz J, Mazuyer D, Tysoe WT. Exploring mechanochemical reactions at the nanoscale: theory versus experiment. Phys Chem Chem Phys 2023. [PMID: 37255477 DOI: 10.1039/d3cp00980g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Mechanochemical reaction pathways are conventionally obtained from force-displaced stationary points on the potential energy surface of the reaction. This work tests a postulate that the steepest-descent pathway (SDP) from the transition state to reactants can be reasonably accurately used instead to investigate mechanochemical reaction kinetics. This method is much simpler because the SDP and the associated reactant and transition-state structures can be obtained relatively routinely. Experiment and theory are compared for the normal-stress-induced decomposition of methyl thiolate species on Cu(100). The mechanochemical reaction rate was calculated by compressing the initial- and transition-state structures by a stiff copper counter-slab to obtain the plots of energy versus slab displacement for both structures. The reaction rate was also measured experimentally under compression using a nanomechanochemical reactor comprising an atomic-force-microscopy (AFM) instrument tip compressing a methyl thiolate overlayer on Cu(100) (the same system for which the calculations were carried out). The rate was measured from the indent created on a defect-free region of the methyl thiolate overlayer, which also enabled the contact area to be measured. Knowing the force applied by the AFM tip yields the reaction rate as a function of the contact stress. The result agrees well with the theoretical prediction without the use of adjustable parameters. This confirms that the postulate is correct and will facilitate the calculation of the rates of more complex mechanochemical reactions. An advantage of this approach, in addition to the results agreeing with the experiment, is that it provides insights into the effects that control mechanochemical reactivity that will assist in the targeted design of new mechanochemical syntheses.
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Affiliation(s)
- Nicholas Hopper
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
| | - François Sidoroff
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR5513, Ecole Centrale de Lyon, F-69134 Ecully cedex, France
| | - Resham Rana
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
| | - Robert Bavisotto
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
| | - Juliette Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR5513, Ecole Centrale de Lyon, F-69134 Ecully cedex, France
| | - Denis Mazuyer
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR5513, Ecole Centrale de Lyon, F-69134 Ecully cedex, France
| | - Wilfred T Tysoe
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
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Frérot L, Crespo A, El-Awady JA, Robbins MO, Cayer-Barrioz J, Mazuyer D. From Molecular to Multiasperity Contacts: How Roughness Bridges the Friction Scale Gap. ACS Nano 2023; 17:2205-2211. [PMID: 36690336 PMCID: PMC9933612 DOI: 10.1021/acsnano.2c08435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
The tangential force required to observe slip across a whole frictional interface can increase over time under a constant load, due to any combination of creep, chemical, or structural changes of the interface. In macroscopic rate-and-state models, these frictional aging processes are lumped into an ad hoc state variable. Here we explain, for a frictional system exclusively undergoing structural aging, how the macroscopic friction response emerges from the interplay between the surface roughness and the molecular motion within adsorbed monolayers. The existence of contact junctions and their friction dynamics are studied through coupled experimental and computational approaches. The former provides detailed measurements of how the friction force decays, after the stiction peak, to a steady-state value over a few nanometers of sliding distance, while the latter demonstrates how this memory distance is related to the evolution of the number of cross-surface attractive physical links, within contact junctions, between the molecules adsorbed on the rough surfaces. We also show that roughness is a sufficient condition for the appearance of structural aging. Using a unified model for friction between rough adsorbed monolayers, we show how contact junctions are a key component in structural aging and how the infrajunction molecular motion can control the macroscopic response.
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Affiliation(s)
- Lucas Frérot
- Department
of Physics and Astronomy, Johns Hopkins
University, 3400 N. Charles Street, Baltimore, Maryland21218, United States
- Department
of Mechanical Engineering, Johns Hopkins
University, 3400 N. Charles
Street, Baltimore, Maryland21218, United States
| | - Alexia Crespo
- Laboratoire
de Tribologie et Dynamique des Systèmes, École Centrale
de Lyon, CNRS UMR5513, 69134Ecully, France
| | - Jaafar A. El-Awady
- Department
of Mechanical Engineering, Johns Hopkins
University, 3400 N. Charles
Street, Baltimore, Maryland21218, United States
| | - Mark O. Robbins
- Department
of Physics and Astronomy, Johns Hopkins
University, 3400 N. Charles Street, Baltimore, Maryland21218, United States
| | - Juliette Cayer-Barrioz
- Laboratoire
de Tribologie et Dynamique des Systèmes, École Centrale
de Lyon, CNRS UMR5513, 69134Ecully, France
| | - Denis Mazuyer
- Laboratoire
de Tribologie et Dynamique des Systèmes, École Centrale
de Lyon, CNRS UMR5513, 69134Ecully, France
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Delamarre S, Gmür T, Spencer ND, Cayer-Barrioz J. Polymeric Friction Modifiers: Influence of Anchoring Chemistry on Their Adsorption and Effectiveness. Langmuir 2022; 38:11451-11458. [PMID: 36082717 DOI: 10.1021/acs.langmuir.2c01782] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Correlated adsorption and lubricity have been investigated using polymeric friction modifiers, specifically designed with an oleophilic brush-forming block and an anchoring block of comparable length. Through adsorption, rheology, and friction measurements, we have highlighted the existence of boundary layers, whose molecular organization and mechanical properties govern the frictional behavior. We have demonstrated that changing the anchoring chemistry controls the final ordering in the boundary layer. The stability of the surface anchoring governs the onset of repulsion between the polymer layers and the capacity of the layer to withstand shear. The higher degree of molecular order provided by the most firmly anchored polymer to the surface was thereby responsible for the significant friction reduction observed.
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Affiliation(s)
- Sébastien Delamarre
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully Cedex, France
| | - Tobias Gmür
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
| | - Nicholas D Spencer
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zurich, Switzerland
| | - Juliette Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully Cedex, France
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Hemette S, Cayer-Barrioz J, Mazuyer D. Friction setup and real-time insights of the contact under controlled cold environment: The KŌRI tribometer for rubber-ice contact application. Rev Sci Instrum 2018; 89:123903. [PMID: 30599629 DOI: 10.1063/1.5048844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
A friction setup combining real-time ice-rubber contact visualization, force measurement, and a compact controlled cold environment system was developed in order to investigate ice-rubber contact complex tribological response and the various contributions to friction, such as viscoelastic deformation, ice surface melting, adhesion, ice creep, or quasi-liquid layer effect. The cold system was based on a cryogenic bath circulator, an air convection circuit, and several thermal insulation combinations such as silica aerogel and expanded polystyrene. The KŌRI tribometer allows one to reach negative temperatures until -20 °C and to perform tribological experiments for velocity from 50 μm s-1 to 1 m s-1 under load up to 50 N and to simultaneously measure resultant forces until 30 N and visualize the contact in real-time. In parallel, an ice manufacturing unit and a specific protocol were developed to grow a transparent ice disc with a controlled initial roughness and surface state. Real-time and simultaneous visualization of the ice-rubber contact provides additional data, such as the apparent contact area and the mean size of a real contact spot during friction, after adequate and dedicated image processing. To illustrate the capability of the KŌRI tribometer, rubber-ice friction measurements were performed at -10 °C and the results are presented here, as a function of time and velocity.
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Affiliation(s)
- Sylvain Hemette
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, École Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully Cedex, France
| | - Juliette Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, École Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully Cedex, France
| | - Denis Mazuyer
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR 5513, École Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully Cedex, France
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Crespo A, Morgado N, Mazuyer D, Cayer-Barrioz J. Effect of Unsaturation on the Adsorption and the Mechanical Behavior of Fatty Acid Layers. Langmuir 2018; 34:4560-4567. [PMID: 29583006 DOI: 10.1021/acs.langmuir.8b00491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Adsorption, self-organization, and mechanical properties of different fatty acid layers under different confinement states have been investigated as a function of the presence and conformation of one unsaturation in their aliphatic chain. In situ characterization, at the molecular level, was performed with the ATLAS molecular tribometer, in terms of rheology, forces, and thickness of confined fluid. The results demonstrate that the fatty acids adsorb on the surfaces by weak interactions and form viscoelastic films with a thickness of about 15 Å on each surface. The adsorption kinetics, the packing of the self-assembled monolayers, and the coverage rate depend on the molecular architecture of the fatty acids and lead to various mechanical behaviors under confinement.
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Affiliation(s)
- Alexia Crespo
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR5513 , Ecole Centrale de Lyon , 36 avenue Guy de Collongue , 69134 Ecully Cedex , France
| | - Nazario Morgado
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR5513 , Ecole Centrale de Lyon , 36 avenue Guy de Collongue , 69134 Ecully Cedex , France
| | - Denis Mazuyer
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR5513 , Ecole Centrale de Lyon , 36 avenue Guy de Collongue , 69134 Ecully Cedex , France
| | - Juliette Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes, CNRS UMR5513 , Ecole Centrale de Lyon , 36 avenue Guy de Collongue , 69134 Ecully Cedex , France
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Yahiaoui M, Rigaud E, Mazuyer D, Cayer-Barrioz J. Forced oscillations dynamic tribometer with real-time insights of lubricated interfaces. Rev Sci Instrum 2017; 88:035101. [PMID: 28372382 DOI: 10.1063/1.4977234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This paper presents an innovative forced oscillations dynamic tribometer, the CHRONOS tribometer, with a lubricated ball-on-flat contact configuration fitted out with an in situ optical visualization system and a triggered high-speed camera. The CHRONOS tribometer generates controlled oscillating kinematics by means of a shaker with a range of strokes from 5 μm to 2.5 mm and an oscillation frequency which can be adjusted from 5 Hz to 250 Hz. Displacement and velocity are measured using a vibrometer. The ball-on-flat mean contact pressure is set between 200 MPa and 600 MPa. During motion, the instantaneous normal and friction forces and the interfacial film thickness distribution (in the nanometer scale) are simultaneously measured. In addition to this instantaneous approach, a more macroscopic approach is developed in terms of moving averages of friction and velocity. Another parameter, the friction-velocity tilt angle, is also introduced. This last parameter may give information on the friction-velocity dependence. Eventually, the experiments performed on the CHRONOS device lead to the representation of synchronized temporal signals of displacement/velocity, friction, and lubricant central film thickness. This superimposition of key parameters reveals time effects introduced by the periodical fluid squeeze and flow in the contact.
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Affiliation(s)
- M Yahiaoui
- Laboratoire de Tribologie et Dynamique des Systèmes-UMR 5513 CNRS, École Centrale de Lyon, 69130 Écully, France
| | - E Rigaud
- Laboratoire de Tribologie et Dynamique des Systèmes-UMR 5513 CNRS, École Centrale de Lyon, 69130 Écully, France
| | - D Mazuyer
- Laboratoire de Tribologie et Dynamique des Systèmes-UMR 5513 CNRS, École Centrale de Lyon, 69130 Écully, France
| | - J Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes-UMR 5513 CNRS, École Centrale de Lyon, 69130 Écully, France
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Fernandez N, Mani R, Rinaldi D, Kadau D, Mosquet M, Lombois-Burger H, Cayer-Barrioz J, Herrmann HJ, Spencer ND, Isa L. Microscopic mechanism for shear thickening of non-Brownian suspensions. Phys Rev Lett 2013; 111:108301. [PMID: 25166716 DOI: 10.1103/physrevlett.111.108301] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Indexed: 06/03/2023]
Abstract
We propose a simple model, supported by contact-dynamics simulations as well as rheology and friction measurements, that links the transition from continuous to discontinuous shear thickening in dense granular pastes to distinct lubrication regimes in the particle contacts. We identify a local Sommerfeld number that determines the transition from Newtonian to shear-thickening flows, and then show that the suspension's volume fraction and the boundary lubrication friction coefficient control the nature of the shear-thickening transition, both in simulations and experiments.
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Affiliation(s)
- Nicolas Fernandez
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Roman Mani
- Computational Physics for Engineering Materials, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Dirk Kadau
- Computational Physics for Engineering Materials, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, 8093 Zurich, Switzerland
| | | | | | - Juliette Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes-UMR 5513 CNRS, École Centrale de Lyon, 69130 Écully, France
| | - Hans J Herrmann
- Computational Physics for Engineering Materials, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, 8093 Zurich, Switzerland
| | - Nicholas D Spencer
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Lucio Isa
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
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Fay H, Meeker S, Cayer-Barrioz J, Mazuyer D, Ly I, Nallet F, Desbat B, Douliez JP, Ponsinet V, Mondain-Monval O. Polymorphism of natural fatty acid liquid crystalline phases. Langmuir 2012; 28:272-282. [PMID: 22118375 DOI: 10.1021/la203841y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We study the phase behavior in water of a mixture of natural long chain fatty acids (FAM) in association with ethylenediamine (EDA) and report a rich polymorphism depending on the composition. At a fixed EDA/FAM molar ratio, we observe upon dilution a succession of organized phases going from a lamellar phase to a hexagonal phase and, finally, to cylindrical micelles. The phase structure is established using polarizing microscopy, SAXS, and SANS. Interestingly, in the lamellar phase domain, we observe the presence of defects upon dilution, which SAXS shows to correspond to intrabilayer correlations. NMR and FF-TEM techniques suggest that these defects are related to an increase in the spontaneous curvature of the molecule monolayers in the lamellae. ATR-FTIR spectroscopy was also used to investigate the degree of ionization within these assemblies. The successive morphological transitions are discussed with regards to possible molecular mechanisms, in which the interaction between the acid surfactant and the amine counterion plays the leading role.
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Affiliation(s)
- Hélène Fay
- Université de Bordeaux, Centre de Recherche Paul Pascal, UPR CNRS 8641, 115 avenue Schweitzer, 33600 Pessac, France
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Wu-Bavouzet F, Cayer-Barrioz J, Le Bot A, Brochard-Wyart F, Buguin A. Effect of surface pattern on the adhesive friction of elastomers. Phys Rev E Stat Nonlin Soft Matter Phys 2010; 82:031806. [PMID: 21230100 DOI: 10.1103/physreve.82.031806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Indexed: 05/30/2023]
Abstract
We present experimental results for the friction of a flat surface against a hexagonally patterned surface, both being made of PolyDiMethylSiloxane. We simultaneously measure forces of range 10 mN and observe the contact under sliding velocities of about 100 μm/s. We observe adhesive friction on three different pattern heights (80, 310, and 2100 nm). Two kinds of contacts have been observed: the flat surface is in close contact with the patterned one (called intimate contact, observed for 80 nm) or only suspended on the tops on the asperities (called laid contact, observed for 2100 nm). In the range of velocities used, the contact during friction is similar to the static one. Furthermore, our experimental system presents a contact transition during friction for h=310 nm.
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Affiliation(s)
- Fanny Wu-Bavouzet
- Laboratoire Physico-Chimie Curie, CNRS UMR 168, Institut Curie Section Recherche, Paris, France
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Abstract
The sliding dynamics of a confined adsorbed polymer layer is investigated at the nanoscale. A combined mechanical and physical approach is used to model the rheology and structure of the adsorbed layer. The confinement at short distances governs the nanotribological behavior of the polymer layer formed close to the surface. It appears that the Amontons' proportionality between frictional and normal stresses does not hold here: the higher the contact pressure, the lower the friction. Besides, the sliding stress is strongly dependent on the velocity: it increases with the sliding velocity. Using a model based on the kinetics of formation and rupture of adhesive bonds between the two shearing surfaces theoretically accounts for the behavior of this system. This approach allows us to correlate the frictional properties to the molecular organization on the surfaces.
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Affiliation(s)
- Juliette Cayer-Barrioz
- Laboratoire de Tribologie et Dynamique des Systèmes-UMR 5513 CNRS/Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully Cedex, France.
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Abstract
The nanotribological behavior of self-assembled monolayers is investigated. The latter accommodate friction through transient relaxation and dilatancy effects whose kinetics depends on the structure of the confined layers. Thus, the molecular ordering onto the surfaces controls the level and the stability of the friction coefficient. Moreover, the behavior of these systems is theoretically accounted for using a model based on the kinetics of formation and rupture of adhesive bonds between the two shearing surfaces with an additional viscous term.
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Affiliation(s)
- Denis Mazuyer
- Laboratoire de Tribologie et Dynamique des Systèmes-UMR 5513 CNRS, Ecole Centrale de Lyon, 36 avenue guy de collongue, 69134 Ecully Cedex, France
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Cayer-Barrioz J, Ferry L, Frihi D, Cavalier K, Séguéla R, Vigier G. Microstructure and mechanical behavior of polyamide 66-precipitated calcium carbonate composites: Influence of the particle surface treatment. J Appl Polym Sci 2006. [DOI: 10.1002/app.22826] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cayer-Barrioz J, Tonck A, Mazuyer D, Kapsa P, Chateauminois A. Nanoscale mechanical characterization of polymeric fibers. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20323] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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