Equilibrium configurations of liquid droplets on solid surfaces under the influence of thin-film forces Part II. Shape calculations

The appropriate augmented Young-Laplace equation for cylindrical and axisym metric geometry is solved numerically to generate equilibrium drop and bubb le shapes for Various interaction-potential curves, P(h), where h is the di stance of the liquid-vapor interface from the solid substrate. Order-of-red uction integration of the augmented Young-Laplace equation for the cylindri cal geometry serves as a useful tool in determining how the characteristics of the interaction potential and the associated parameters affect droplet shapes. In particular, a graph of P(h) +p(c)h, where p(c) is the capillary pressure, versus h codifies the wide variety of drop and bubble shapes that arise from a given interaction-potential isotherm. Examples of shapes calc ulated are drops or bubbles with and without films, wiggly drops or bubbles , drops or bubbles that exhibit multiple equilibrium shapes, and drops with step structures. Specific conditions are provided for each type of drop sh ape. (C) 1999 Elsevier Science B.V. All rights reserved.