Can a polymer brush trap a wetting layer?

Abstract

Grafted polymer layers are well known as stabilizing agents in colloidal dispersions. Here we show how these polymer ‘‘brushes’’ may also deeply modify wetting phenomena by favoring the formation of stable wetting layers of microscopic size. We discuss in particular the influence of a solvated polymer layer on the wetting properties of the substrate by a second minority solvent. In the case where the brush prefers the second solvent, this solvent may be drawn to the interface even if it would not ordinarily wet the substrate. On the contrary, a solvent that ordinarily forms a thick wetting layer may be partially inhibited from doing so (forming a thin trapped layer) if it is a worse solvent for the brush.