A Monte Carlo study of wetting transitions in polymer blends confined to a capillary

Abstract

We investigate the problem of wetting transitions in polymer blends confined to a slitlike adsorbing capillary of thickness H by Monte Carlo methods. Two paths for capillary wetting are considered, either along a path of increasing temperature, T, or increasing surface chemical potential, μ1. We find that H can be thought of as an additional thermodynamic parameter which controls the nature of the transitions. We find that there exists a capillary critical separation, Hc. For separations less than Hc the blend falls in the one phase region of the phase diagram. Above Hc there exists a separation Hbulk, where the polymer blend begins to show bulk behavior. Hbulk is shown to separate regions of first order transitions (H < Hbulk) from critical wetting transitions (H ≥ Hbulk). Along a path of constant T and increasing μ1 we find for 2ξ