Monte Carlo simulation of phase-separated self-assembled films

Phase-separation of self-assembled monolayer (SAM) made from binary components is studied. The interaction between the molecules in the SAM films was estimated by a simple Monte Carlo simulation. The molecules are arranged on the two-dimensional triangular lattice sites and exchange their position with the probability determined from the molecular interaction energy calculated over the Nth nearest neighbors. One-to-one mixture with lattice sizes of 128 x 128, 256 x 256, and 512 x 512 was calculated, and the threshold energy for the domain formation was independent of the size. On the other hand, the domain shape and size depended on the calculation method and the lattice size. The threshold energy at 300 K corresponds to the estimated interaction between the hydrocarbon chains of 7-8 carbon atoms. (C) 1998 Elsevier Science B.V. All rights reserved.