Shape of a Liquid Film

The left term is the local capillary pressure caused by the local curvature (rf + )  

This expression describes the actual shape of the fluid interfaces. Pc is the capillary pressure caused by the curvature ofthe meniscus far away from the film. It is given by the Laplace equation and determined by the curvature of the meniscus (indicated by rb). In the meniscus far away from the film where h is so large that II is zero, the curvature is equal to the curvature of the meniscus. In the transition zone, interfacial forces come into play and II yf 0. Since Pc is constant, the local curvature decreases below that in the meniscus. In the film region, the local curvature is zero, +rf ) = 0, and the inner pressure of the gas phase is fidly balanced by the disjoining pressure in the film. 

---

Problem What is the shape of a liquid film ascending a plate when van der Waals forces come into play ... 

---