A5090209414- Spectroscopy and Quantum Chemical Studies
- Lipid Membrane Structure and Behavior
- Surfactants and Colloidal Systems
- Electrostatics and Colloid Interactions
- Force Microscopy Techniques and Applications
- Polymer Surface Interaction Studies
- Nuclear Physics and Applications
- Pickering emulsions and particle stabilization
- nanoparticles nucleation surface interactions
- Block Copolymer Self-Assembly
- Particle Accelerators and Free-Electron Lasers
- Material Dynamics and Properties
- Advanced X-ray Imaging Techniques
- Nuclear physics research studies
- Surface Roughness and Optical Measurements
- Surface Modification and Superhydrophobicity
- Nanopore and Nanochannel Transport Studies
- Phase Equilibria and Thermodynamics
- Characterization and Applications of Magnetic Nanoparticles
- Particle accelerators and beam dynamics
- Iron oxide chemistry and applications
- X-ray Spectroscopy and Fluorescence Analysis
- Fluid Dynamics and Thin Films
- Gold and Silver Nanoparticles Synthesis and Applications
- Nanofabrication and Lithography Techniques
European Synchrotron Radiation Facility
2008-2025
Synchrotron soleil
2014-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2007-2020
Société Française de Cardiologie
2020
Université Paris-Saclay
2015-2020
BP (United Kingdom)
2016
Institut Rayonnement-Matière de Saclay
2008-2015
CEA Paris-Saclay
2006-2015
Centre National de la Recherche Scientifique
2003-2015
Infection et inflammation
2012-2015
(i) A film of a nonwetting liquid is not stable. If it thick (thickness e ≥ 1000 Å) metastable and evolves via nucleation growth dry spot. thin, unstable against spinodal decomposition (amplification thermal undulations) breaks into microscopic droplets size ~e 2 /a (a = molecular size), (ii) made with wetting tends to shrink whenever < S (the equilibrium thickness the layer). Contrary case where patch controlled by capillary forces, central role for drying in played long-range only...
We have measured the contact angle of microsized and nanosized alkane droplets partially wetting a model substrate using true noncontact atomic force microscopy. The large range droplet sizes accessible this technique allowed us to determine line curvature dependence with unprecedented accuracy. Whereas previous studies aimed at explaining such by tension effect, our results calculations on system exclude an effect point extreme sensitivity weak heterogeneities confirmed numerical simulations.
A single lipid molecular bilayer of 17 or 18 carbon chain phosphocholines, floating in water near a flat wall, is prepared the gel phase and then heated to fluid phase. Its structure (electron density profile) height fluctuations are determined by using x-ray reflectivity nonspecular scattering. By fitting off-specular signal that calculated for two-dimensional membrane Helfrich Hamiltonian, we determine three main physical quantities govern fluctuations: The wall attraction potential...
The phase inversion of water-toluene emulsions stabilized with a single thermo- and pH-sensitive copolymer occurs through the formation multiple emulsions. At low pH ambient temperature, oil in water are formed which transform into highly stable at pHs immediately lower than border. higher pHs, emulsion turns one.
The diffuse scattering of x rays by thin films limited rough interfaces is presented theoretically in terms height–height correlation functions. method employed, analogous to the use Green functions, allows a rigourous treatment down grazing incidences. An expression for scattered intensity obtained from cross section. results are then discussed using model function, and interpretation x-ray reflectivity experiments reexamined. We show that off-specular scans yield direct information about...
Water-dispersed silica nanoparticles (NPs) do not adsorb to the interface between immiscible bulks of water and hexane. Adding, however, a surfactant (cetyltrimethylammonium bromide, CTAB) induces formation NP monolayer (ML) at this model liquid–liquid interface. We determined ML's structure in situ deeply buried planar water–hexane interfaces with sub-nanometer resolution by high energy X-ray reflectivity. Detailed modeling data yields NPs' interfacial concentration immersion depth,...
We have investigated the small-scale structure of liquid-vapor interface using synchrotron x-ray scattering for liquids with different molecular structures and interactions. The effective momentum-dependent surface energy first decreases from its macroscopic value due to effect long-range forces, then increases increasing wave vector. results are analyzed a recent density functional theory. large wave-vector increase is attributed bending which local nonlocal contributions equally important.
Thermally induced capillary waves on a monolayer of behenic acid water have been investigated by x-ray reflectivity. The corresponding roughness is measured as function the surface pressure. experimental data are discussed using theory thermal fluctuations. A strong decrease in observed at transition to solid state. This striking feature attributed rigidity phase whose value has determined.
X-ray scattering investigations of surfaces and interfaces in soft-condensed matter are reviewed. Both high-resolution structural determinations the direct space fluctuations with long-range correlations requiring a high resolution Fourier discussed. All cross-sections for diffraction or diffuse derived within unified frame, experimental aspects related to their measurement discussed detail. The general principles illustrated by various examples studies liquid-vapour interface, Langmuir...
We have investigated the surface composition of alkali-halide aqueous solutions using grazing incidence x-ray fluorescence. Using mixtures salts as a means to enhance short-range effects, small differences in concentration over few angstrom could be resolved, with, for example ${\mathrm{I}}^{\ensuremath{-}}$ or ${\mathrm{Br}}^{\ensuremath{-}}>{\mathrm{Cl}}^{\ensuremath{-}}$. In order explain our data, we need include an effective potential accounting (\AA{}) solvent mediated couplings,...
The role of thin films in different situations wetting has been investigated by x-ray reflectivity, a technique that allows an independent determination their thicknesses, densities, and roughnesses, using nonvolatile siloxane oil spreading on kinds surfaces. microscopic droplet involves at least two stages: the development ``tongue'' molecular thickness controlled parameter friction substrate is followed surface diffusion process. final stages are shown to be largely dependent...
The swelling dynamics of the ultrathin polyacrylamide (PAM) spin-coated films in saturated vapor D2O and H2O were studied using neutron X-ray reflectivity. A uniform scattering length density (SLD) profile represents dry PAM films, whereas SLD profiles corresponding to swelled characterized with a decreasing solvent concentration along film thickness from top surface film/substrate interface. diffusion mechanism into was found be non-Fickian process, as coefficient observed function...
Microscopic measurements that provide direct information in nanometer length scales are essential to obtain a proper understanding of the interfacial reactions form nanostructured materials. We present here results synchrotron X-ray scattering study formation and ordering gold nanoparticles at toluene−water interface through reduction reaction. The observed reflectivity diffuse data show monolayer "magic clusters" water−toluene interface. Each cluster consists 13 with about 12 Å diameter,...
Formation of condensed films nanoparticles having small ratio metal-core-diameter to organic-shell-thickness is desired for several applications in nanotechnology. We report here results a X-ray scattering study carried out understand structure and morphology monolayer such gold-core thiol-shell directly on the water surface before undergoes continuous transition bilayer. Our demonstrate buckling over large pressure range (1 15 mN/m). The buckled state exhibits reversibility decompression...
We have performed neutron reflectivity measurements on a monolayer of charged diblock copolymers in Langmuir trough, and determined precise density profiles the polyelectrolyte brush at different densities. obtain good agreement with existing self-consistent field computations, both for osmotic salted regime. show that brush's thickness increases density.
The buckling of a two-dimensional polymer network at the air-water interface has been evidenced by grazing incidence x-ray scattering. A comprehensive description inhomogeneous octadecyltrichlorosilane polymerized film was obtained atomic force microscopy and scattering measurements. occurs with characteristic wavelength \ensuremath{\simeq}10 \ensuremath{\mu}m.