CONTACT-ANGLE RELAXATION DURING THE SPREADING OF PARTIALLY WETTING DROPS

We apply the molecular kinetic theory of wetting to the relaxation of the dynamic contact angle during the spreading of liquid droplets on s olid surfaces. Experimental data have been obtained for several solid- liquid combinations and are successfully fitted using the theory. Phys ical parameters are extracted and interpreted in terms of the microsco pic characteristics of the liquid and the solid. We also show that dro plet spreading and forced wetting can be described by the same equatio ns. a comparison is made between the results obtained within the molec ular-kinetic framework and those obtained with conventional hydrodynam ic theory.