Spreading charged micro-droplets

Abstract

This paper considers the analysis of the BF model of the spreading of a charged microdroplet on a flat dielectric surface whose spreading is driven by surface tension and electrostatic repulsion. This model assumes the droplets are circular and spread according to a power law. This leads to a third order nonlinear ordinary differential equation on $[0,1]$ that gives the evolution of the height profile. We prove that there is only one such solution that is smooth on all of $[0,1]$. There are other solutions that are continuous on $[0,1]$, but not differentiable at $x=1$. For these we describe the precise behavior of the solutions at $x=1$.