Wetting of a Polymer Brush by a Chemically Identical Polymer Melt

Abstract

We present a theoretical study of the conformations of a polymer brush (made of linear macromolecules chemically anchored to a flat, solid interface) when it is exposed to a molten, compatible polymer. At large brush grafting densities σ and melt molecular weights P, the melt only penetrates the brush over a distance λ that is small, compared to the brush thickness. For P > N2/3σ-2/3, the penetration length λ ≈ aσ-1/3N1/3 (Leibler et al. Proceedings of the OUMS Conference, Osaka, Japan, June, 1993) is associated with partial wetting. For P < N2/3σ-2/3, although wetting is complete (as was predicted by Leibler et al), we find that penetration is still partial: λ = aσ-1NP-1. There should be implications in interfacial rheology and in wetting dynamics.