Microscopic and macroscopic contact angles

Abstract

A simple relation is derived between the microscopic and macroscopic angles of contact of a fluid interface with a solid by taking into account the interaction of the interfaces in the region of contact. It is also shown how the macroscopic angle can be related to the perturbed interfacial tensions. Both angles are a property of the three phases in contact, independent of geometry and weak gravitational fields. Finally, calculated profiles of axially symmetric fluid interfaces in the neighbourhood of a planar solid surface are compared with those that would occur in the absence of interaction between the interfaces.