Monte Carlo simulations of nanoconfined n-decane films

Grand canonical ensemble Monte Carlo simulations of thin films of fluid n-d ecane confined between two plane-parallel, structureless walls were perform ed using the configurational bias method. The results indicate that special attention has to be paid to the way in which configuration space is sample d. A key quantity in the study is the solvation pressure p(s(z)), which is a damped oscillatory function of wall separation s(z). The intensity of the se oscillations is a consequence of both the formation of discrete molecula r layers in the fluid parallel with the walls and the presence of isolated n-decane chains interconnecting neighboring layers, in that one end of the chain belongs to one layer and the other end to its neighbor. By means of D erjaguin's approximation, the solvation force from p(s(z)), which is freque ntly measured in experiments employing the surface forces apparatus, was ca lculated. The solvation force exhibits damped oscillations superimposed on a repulsive component, an effect which is ascribed to the presence of chain s interconnecting neighboring fluid layers.