Determination of static and dynamic interactions between monodisperse, charged silica spheres in an optically matching, organic solvent

Abstract

A light scattering study is presented on static and dynamic interactions between monodisperse, charged silica spheres suspended in an optically matching, salt free mixture of ethanol and toluene up to volume fractions of 10%. The static structure factor S(K), well described by calculations in the RMSA approximation, is combined with the wave vector (K) dependent (short‐time) diffusion coefficient D_e(K) to give the function H(K) which represents the hydrodynamic interactions. From H(K), obtained for the first time for charged particles, we conclude that the long‐range electrostatic repulsion between the spheres has a pronounced influence on the hydrodynamics of large‐scale, collective particle motions, whereas small‐scale single‐particle diffusion is relatively unaffected.