Analytical theories of the steric stabilization of colloidal dispersions

Abstract

Analytical theories are developed for the steric stabilization of colloidal spheres and flat plates by monodisperse tails. It is proposed that the reason for the failure of previous theories to predict the correct distance dependence of the repulsion resides in their neglect of lateral interactions between adjacent stabilizing chains. Theories are therefore formulated that implicitly allow for these lateral interactions. All that need be specified is the mathematical form of the relevant segment density distribution functions. Two models are examined in detail: a constant segment density model and a combined constant segment density and near symmetrical gaussian model. The latter gives the better agreement with experimental results. Both models, however, describe the distance dependence of the repulsion reasonably well over quite a wide range of separations.