THE INFLUENCE OF INTERMOLECULAR FORCES ON THIN FLUID LAYERS

An expression for the disjoining pressure for fluid in the shape of a wedge is obtained in a form that incorporates the contact angle. This expression is used to construct the equation for the shape of the free surface of a thin drop of fluid governed by capillarity, gravity, and van der Waals' forces. The change in the shape and radius of the drop when intermolecular forces are included is found. The dynamical equation for a fluid layer incorporating all these forces and viscosity is obtained, and solved to determine the draw-down of the edge of a layer of fluid resting on a gently inclined plate when the plate is moving in its own plane.