Wetting Transition of Water on Graphite and Other Surfaces

Abstract

A wetting transition occurs when the contact angle of a liquid drop on a surface changes from a nonzero value to zero. Such a transition has never been observed for water on any solid surface. This paper discusses the value of the temperature T w at which the transition should occur for water on graphite. A simple model, previously used for nonpolar fluids, predicts the value of T w as a function of the well depth D of the adsorption potential. While D is not well known for the case of water/graphite, the model implies that T w is likely to fall in the range 350−500 K. Experimental search for this transition is warranted. Water-wetting transition temperatures on other surfaces are also discussed.