Wetting and drying of a rigid substrate under variation of the microscopic details

Wetting and drying of a rigid substrate by a Lennard-Jones fluid in molecular dynamics simulations is reported. The size of the substrate particles, being smaller than the fluid particles in former simulations, is now taken to be equal to, respectively, larger than, that of the fluid particles. Recently, for the latter type of system a first-order drying transition has been reported. Like before we find a continuous-like transition for all systems considered. This also holds for substrates with incompletely-filled top layers, the so-called molecularly rough surfaces. All systems studied behave qualitatively alike, but inconsistencies are found in the solid-vapour surface tension on approach of the wetting transition and for the solid-fluid surface tension in general. (C) 1998 Elsevier Science B.V. All rights reserved.