Structure factors of charged bidispersed colloidal suspensions

Abstract

In the present study, the effects of charge bidispersity on static structure factors of dilute charged aqueous colloidal suspensions, for compositions covering the full molar fraction range, are investigated using static light-scattering experiments and integral equation theory. The suspensions under study are made from different charged polystyrene particles with an average diameter of 100 nm. The experimentally-observed static structure factors are then compared with theoretical results obtained from the hypernetted chain approximation. The values of both charges are determined by fitting the scattering data of the two pure components and are kept constant for the mixtures. In order to fully describe the experimental data, the effects of the intrinsic polydispersity have to be taken into account. It is found that the height of the main peak of the measured static structure factor, SM(q), changes monotonically as a function of the composition.