Study of adsorption of binary mixtures on disordered substrates

The adsorption of binary mixtures on solid heterogeneous substrates is stud ied by Monte Carlo simulation in the framework of the lattice gas model. Th e energy of the surface has been modeled by considering two kind of adsorpt ion sites, deep and shallow traps, forming square homogeneous patches of di fferent sizes; these adsorption domains have been distributed either at ran dom or in chessboard-like lattice to obtain simple heterogeneous topographi es. The adsorption process has been monitored through total and partial iso therms and differential heats of adsorption corresponding to both species o f the mixture, for different values of the parameters involved in the model (lateral interactions, energy gap between deep and shallow patches) and di fferent topographies. A rich variety of behaviors is found and analyzed in the context of the lattice gas theory. (C) 2001 Elsevier Science B.V. All r ights reserved.