Square-well fluids in confined space with discretely attractive wall-fluid potentials: critical point shift

In this work the effects of the wall-fluid interaction on the critical point shift are studied by using a discrete and attractive wall-fluid interaction and density functional theory. In contrast to the previous assumption, it is found that the dependence of critical temperature shift on the wall-fluid interaction does not simply show a monotonic manner, but increases with the strength of the interaction for weak surfaces, then decreases for strong surfaces. The similar trend holds for the systems with different fluid-fluid interactions and different confined spaces. Unlike the capillary critical temperature, the critical density of square-well fluids in a confined space increases monotonically as the wall-fluid interaction becomes more attractive.