Dynamic contact angles on moving plates



A simple model for advancing dynamic menisci of the interface between two immiscible fluids is proposed on the hypothesis that there is a monomolecular film which precedes an apparent contact line and that a frictional force due to the solid surface is balanced with the interfacial tension forces on the film. An analytical solution for dynamic contact angles on vertical and inclined solid surfaces of plates is obtained as a function of the interfacial capillary number, the static contact angle, and the parameters of Langumuir's duplex film model. An analytical solution for dynamic meniscus heights is also derived. The analytical solutions are compared with previous experimental data. The agreement between the theoretical and experimental results is found to be fairly good, average deviations being 3.8 and 12%, respectively, for dynamic contact angles and dynamic meniscus heights at the solid surface.