Direct evidence supporting nonlocal hydrodynamic influence on the dynamic contact angle

Abstract

The dynamic contact angle formed when a liquid sheet impinges vertically onto a moving substrate is measured as a function of sheet flow rate for a series of substrate speeds. Usual analyses would assume that the dynamic contact angle were a function solely of material properties and substrate speed. In an earlier paper [T. D. Blake, M. Bracke, and Y. D. Shikhmurzaev, Phys. Fluids 11, 1995 (1999)] it was shown, through indirect measurements, that this is not the case. Despite this experimental evidence, there remains little consensus in the literature. The new data reported here provide further support for nonlocal effects, but in a more direct way. © 2006 American Institute of Physics.