Combined neutron reflectometry and rheology

TL;DR

This paper introduces a novel method combining neutron reflectometry and rheology to study the structural response of liquids and polymers at solid interfaces under shear, revealing how surface energy influences interfacial structure and viscoelastic properties.

Contribution

It presents an integrated experimental approach that simultaneously measures structural and rheological properties at the nanoscale during shear deformation.

Findings

Interfacial structure changes under shear depend on surface energy.

Structural changes correlate with variations in storage and loss modulus.

Method enables detailed nanoscale analysis of complex fluids under stress.

Abstract

We have combined neutron reflectometry with rheology in order to investigate the solid boundary of liquids and polymers under shear deformation. Our approach allows one to apply a controlled stress to a material while resolving the structural arrangements on the sub nanometer length scale with neutron reflectivity, off-specular and small angle scattering at the same time. The specularly reflected neutron intensity of a 20 % by weight solution of the Pluronic F127 in deuterated water is evaluated. We find pronounced changes in the near interface structure under applied deformation for surfaces with different surface energies, which are correlated with changes in the storage and loss modulus.