Monte Carlo simulations of mixed monolayers

Results are presented of Monte Carlo calculations for self-assembled monolayer systems consisting of binary mixtures of long-chain alkyl thiols of different lengths adsorbed on a gold surface. A sampling scheme is used in which largescale conformational changes are made to a trial molecule in a single move, supplemented by attempted interconversions of long and short chains. A marked trend towards segregation of the two species is observed, and the outer regions of the monolayers are found to be conformationally more disordered than the inner parts; both effects are most pronounced when the concentration of long chains is low.