Effects of Electric Field on the Vapor–Liquid Equilibria of Nanoconfined Methanol and Ethanol

The effects of the electric field on the vapor–liquid equilibria of methanol and ethanol confined in a graphitic slit pore of width 4 nm using molecular dynamics simulations are reported. The vapor–liquid critical temperature of methanol gets suppressed under confinement. The external electrical field further decreases the critical temperature with increasing electric field strength up to E = 1.5 V·nm–1. Surprisingly, a further increase in the electric field strength reverses the critical temperature behavior and is seen to increase with increasing electric field. The reversible behavior of the critical temperature with the electric field is also seen for nanoconfined ethanol at approximately 1.5 V·nm–1. The critical density, on the other hand, is found to continuously decrease with increasing electric field strength. Application of an external electric field results in the decrease in vapor and liquid densities. The coordination number in the liquid phase is found to decrease first with increasing electric field until E = 1.5 V·nm–1 and then increases with a further increase in the electric field, confirming the observed trend in the critical temperature according to the mean field theory. Orientational order of nanoconfined methanol and ethanol, on the other hand, is found to increase with increasing electric field.