SPREADING OF A THIN WETTING FILM - MICROSCOPIC APPROACH

In this paper we present a microscopic model description of spreading kinetics of a monomolecularly thin wetting film climbing from a bath o f liquid along a vertical solid wall. We find analytically that both t he linear extension and the mass (number of particles) of the film gro w in proportion to root t, in accord with experimental observations. W e also analyze the details of the fine structure of the wetting film a nd determine explicitly the concentration profile along the film and c oncentration gradients at the tip of the film and in the vicinity of t he liquid bath. We show that the essential physical mechanism responsi ble for film's growth is associated with the diffusive transport of va cancies from the tip of the film to the liquid bath, where they are fi lled with fluid particles.