Structure and associated properties of concentrated SiO₂ sols in dilute salt solutions

Abstract

Using the Verwey-Overbeek potential (VO) function the various liquid-state properties of SiO2 sols in dilute salt solutions have been evaluated under the mean spherical model approximation (MSMA). The structure factors of these SiO2 sols predicted by this model are compared with results obtained from small-angle neutron scattering experiments by Ramsay et al. Fourier transformation of these structure factors have been performed to obtain the radial distribution functions (RDF), and from these RDF's we computed coordination numbers of the sol particles. The interparticle distanced c of sol particles has been obtained from the peak position in structure factorS(k) by using the Bragg's equation. The surface potential Ψ_s of the oxide sols has been determined from the amplitude (A) of the VO potential. The present calculations clearly indicate some sort of ordering in the sols system. It is gratifying to note that the present theoretical calculations could reproduce the available observed results very satisfactorily with respect to structure factor and other data.