Substrate morphology and particle adhesion in reacting systems

This paper describes an effort to measure and model changes in the adhesion of micron-scale particles to substrates in systems in which chemical reactions are occurring. Contact interactions between polystyrene latex spheres and silicon substrates (with surface oxide) immersed in aqueous KNO3 solutions were studied. Two important results were obtained. First, it was shown that the AFM can be employed to monitor, in situ, changes in adhesive interactions induced by surface chemical reactions in this system. Second, the morphology of the interacting surfaces plays a controlling role in particle adhesion. In particular, for this system, changes in roughness of the substrate changed the interaction force by nearly 90%. (C) 2000 Academic Press.