Neutron reflectivity for soft matter

Abstract

Specular neutron reflectivity is a technique enabling the measurement of coherent neutron scattering length density profile perpendicular to the plane of a surface or interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5Å up 5000 Å. It is a scattering technique that averages information over the entire surface and it is therefore not possible to obtain information on correlations in the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, negligible absorption, low energy of the incident neutrons) makes it particularly interesting in the fields of soft matter and biophysics. This course is composed of three parts describing respectively its principle, the experimental aspects (diffractometers, samples), and some scientific examples of neutron reflectometry focusing on the use of contrast variation to probe polymeric systems.

An introduction to neutron reflectometry

“…The most interesting interfaces are then liquid/liquid interfaces and air/water interfaces. However, there are only very sparse studies probing true liquid/water interfaces by NR since this is something hardly challenging for some reasons that are detailed elsewhere [14]. Thus, in practice, liquid/water interfaces are replaced by experiments at solid/water interfaces where membranes are deposited on solid substrates, as depicted in the book section written by Gerelli.…”

The evolution of surface structure during simulated atmospheric ageing of nano-scale coatings of an organic surfactant aerosol proxy

“…NR is described in detail elsewhere. 61,62 Here, we summarise the salient points of the technique. NR was carried out at the ISIS neutron and muon source (UK) on the INTER beamline and on the FIGARO beamline at the Institute Laue-Langevin (France).…”

Introduction to soft matter and neutron scattering

“…If the surface is a nanoparticle, then small-angle scattering can be used to access the polymer structure [81,[127][128][129][130]. If on the other hand, the surface is flat, then reflectometry and possibly GISANS are the methods of choice [95,[131][132][133].…”

“…Jean-Marc Zanotti et al present inelastic and quasi-elastic scattering applied to soft matter [26]. Finally, Fabrice Cousin and Alexis Chennevière discuss neutron reflectivity aiming at density profiles perpendicular to surfaces [95], and Max Wolff, the main organizer of this winter school with Fabrice Cousin, introduces grazing incidence scattering capable of revealing in-surface structures [96].…”