Studies of binary liquid mixtures in cylindrical pores: phase separation, wetting and finite-size effects from Monte Carlo simulations

We have used Monte Carlo simulations in the semi-grand ensemble to study the wetting behavior and phase separation of a simple binary liquid mixture confined in a cylindrical pore. Using “multicanonical” simulations and histogram-reweighting methods we can determine the coexistence of complete-wetting and partial-wetting systems in the (T,X) plane. We present results for several different pore systems, with varying degrees of selectivity for one component of the mixture. We discuss the dependence of the phase diagram and probability distribution function of the mole fraction on pore length, and consider the behavior of these systems in the limit of long pores.