DLVO interaction between rough surfaces

The interaction energy between microscopic bodies is almost exclusively determined assuming perfectly smooth and geometrically regular surfaces. Quite often, such interactions fail to explain several colloidal phenomena. These inexplicable behaviors of colloidal systems are generally ascribed to surface chemical and morphological heterogeneities. Here, we employ the surface element integration technique to determine the interaction energy between surfaces containing morphological heterogeneity. Random asperities are generated to represent surface morphological heterogeneity (roughness), and their influence on the DLVO interaction potential is investigated. Incorporation of surface roughness causes a significant reduction in the repulsive interaction energy, the extent of which depends on the size of the asperities and their densities on the surface. Predictions of interaction energy indicate that the DLVO interaction energy profiles for rough surfaces deviate significantly from those derived assuming perfectly smooth surfaces, particularly at very short separation distances.