EFFECT OF ROUGHNESS ON ENERGY OF REPULSION BETWEEN COLLOIDAL SURFACES

Surface roughness plays a very important role in particle deposition a nd coagulation, especially in the presence of repulsion forces. A simp le model of rough surfaces is proposed in this work for evaluating dou ble-layer interactions. The model allows estimation of the tangential forces between two surfaces by taking into account the interaction of their asperities. Analytical and numerical methods are examined for th e solution of the mathematical problem. Their accuracy, stability, and computational efficiency are investigated over a large range of model parameters. The influence of these parameters on the repulsion energy is studied for the case of constant surface potential and asperities smaller than double-layer thickness. The results of the simple model c an be generalized, at least qualitatively, for arbitrary surface rough ness. (C) 1995 Academic Press, Inc.