Small-angle neutron-scattering study of dense sheared silica gels

Abstract

Small-angle neutron-scattering (SANS) shearing experiments on dense colloidal silica suspensions in a H2O-D2O medium are reported for the wave vector range 0.03<Q(nm-1)<0.8, at volume fractions φ=0.1, 0.12, 0.18, 0.24, and 0.3. For the unsheared gels, apparent fractal structures were observed at the lower volume fractions, and a small maximum at a Q corresponding to a contact particle morphology was apparent at all volume fractions. A fractal dimension d=1.60±0.05 was estimated for φ=0.10 and 0.12 by fitting the power law behavior of the structure factor. Shear induces an apparent fractal domain into the dense gels and enhances the contact particle structure. Show more