A Hydrodynamic Model of Dynamic Contact Angle Hysteresis.

摘要

A qualitative hydrodynamic description of dynamic contact angle hysteresis is developed in terms of the interaction of capillary,viscous,and disjoining forces by considerating the slow motion of a fluid-fluid interface being driven through a capillary tube by an applied pressure gradient. The interfacial stress boundary condition is modified to include the effect of the disjoining pressure. The method of matched asymptotic expansion is then used to obtain the equations which describe the contact angle region and thereby to define the dynamic contact angle. The analysis is limited to small contact angles. The resulting equations describe some of the distinguishing characteristics of the advancing and receding interfaces. The initial velocity dependence of the receding contact angle and of the thickness of the deposited film of the receding interface of a wetting liquid are determined as functions of the capillary,viscous,and disjoining forces. (Author)