Influence of surface roughness on the quartz crystal microbalance response in a solution: New configuration for QCM studies

The effect of surface roughness on a quartz crystal microbalance (QCM) response in contact with a liquid has been investigated. A perturbation theory was used for the description of the effect of slight roughness and an approach based on Brinkman's equation was used for strongly rough surfaces. In the latter approach, one treats the flow of a liquid through a non-uniform surface layer as the flow of a liquid through a porous medium. Our description includes both the effect of viscous dissipation in the interfacial layer and the effect of the liquid mass rigidly coupled to the surface. A relation between QCM response and the interface geometry has been found. We suggested a new approach to study the QCM response in liquids that provides an effective way to analyse the effect of roughness. The models discussed here can be used for the treatment of QCM response of rough electrode surfaces, of porous deposited films, and of surface polymer films.