Phase transition and crossover behavior of colloidal fluids under confinement

We report a molecular simulation study on the non-monotonic behavior of critical temperature, Tcp, of a confined Yukawa fluid. Close to the adhesive hard sphere (AHS) range of the surface–fluid interaction, Tcp monotonically increases with increasing surface–fluid interaction range. Subsequently, after a certain threshold value, depending on the surface interaction well depth, Tcp decreases monotonically with further increase in the surface interaction range. On the other hand, critical density and pressure show increasing monotonic trends with the surface interaction range. The crossover from 3D to 2D behavior for colloidal fluid in attractive pores is observed around a slit width of 14 molecular diameters for the studied system in this work.