LAYERING TRANSITIONS IN CYLINDRICAL PORES

We report grand canonical Monte Carlo simulations and nonlocal density functional theory results for layering transitions that take place in a smooth cylindrical pore with strong fluid-wall interactions. For a pore with a radius of seven molecular diameters and a temperature below the bulk fluid triple point temperature the adsorption isotherms exhibit three distinct layering transitions ending in capillary condensation. The growth of the first layering in the simulation appears supercritical with respect to the layering critical point, but the subsequent layers appear to be true (first-order) transitions. In addition to the layering transitions we also present evidence for a quasi-two-dimensional freezing transition. That is, we observed the first adsorbed layer undergo a transition to a frustrated crystalline state prior to the next layering transition. Finally, for an adsorption isotherm at the bulk triple point there is no evidence for any first-order transitions, indicating that for our system the critical temperature associated with each layering transition does not exceed the bulk triple point temperature. © 1990 American Institute of Physics.