Prospect for characterizing interacting soft colloidal structures using spin-echo small angle neutron scattering

Abstract

Spin-echo small angle neutron scattering (SESANS) presents a new experimental tool for structural investigation. Regarding the material study using neutron scattering it is of particular novel: Due to the action of spin echo encoding, SESANS registers the spatial correlations function in real space, which is distinct from the measurables of conventional elastic neutron scattering techniques. To make viable the use of SESANS in structural characterization, particularly for the interacting colloidal suspensions, we have conducted a theoretical study focusing on understanding the essential features of the SESANS correlation functions obtained from different model systems consisting of particles with uniform density profile (J. Chem. Phys. 132, 174509 (2010)). Within the same framework, we continue to explore the prospect of using SESANS to investigate the structural characteristics of colloid systems consisting of particle with non-uniform intraparticle mass distribution. As an example, a Gaussian model of interacting soft colloids is put forward in our mean-field calculations to investigate the manifestation of structural softness in SESANS measurement. Furthermore, the exploration shows a characteristically different SESANS correlation function for interacting soft colloids, in comparison to that of the referential uniform hard sphere system, due to the Abel transform imbedded in the mathematical formalism bridging the SESANS spectra and the spatial autocorrelation.