DLVO INTERACTION BETWEEN ROUGH SURFACES

The interaction energy between microscopic bodies is almost exclusivel y determined assuming perfectly smooth and geometrically regular surfa ces. Quite often, such interactions fail to explain several colloidal phenomena. These inexplicable behaviors of colloidal systems are gener ally ascribed to surface chemical and morphological heterogeneities. H ere, we employ the surface element integration technique to determine the interaction energy between surfaces containing morphological heter ogeneity. Random asperities are generated to represent surface morphol ogical heterogeneity (roughness), and their influence on the DLVO inte raction potential is investigated. Incorporation of surface roughness causes a significant reduction in the repulsive interaction energy, th e extent of which depends on the size of the asperities and their dens ities on the surface. Predictions of interaction energy indicate that the DLVO interaction energy profiles for rough surfaces deviate signif icantly from those derived assuming perfectly smooth surfaces, particu larly at very short separation distances.