The effect of Surface Wettability on Liquid Film on a Rotating Substrate

Abstract

Predicting the transient thickness of liquid film on a rotating substrate is one of great practical importance. The effect of surface wettability on liquid film has been examined, despite it's an important factor in practical processes. We examine the effect of surface wettability here. Surface wettability is generally defined by the contact angle between the liquid and the substrate. The transient thickness of liquid film was measured for three substrates that have different contact angles. The thinning rate of the liquid film increases when the contact angle increases. We propose a modified Emslie's equation to account for the effect of surface wettability. The transient thickness of liquid film predicted by the proposed equation agrees well with the measured transient thickness.