Interfacial Tension and Spreading Coefficient for Thin Films

We present a modified mathematical expression for the interfacial tension of very thin films. At large thicknesses the modified expression converges to the classic mathematical expression. We use this modified expression to derive an equation for the spreading coefficient as a function of film thickness. The spreading coefficient equation is then used to calculate the equilibrium thickness of a wetting liquid film for a “pancake drop”. Our predictions agree with experimental data. The study is subjected to systems with van der Waals interactions only.