Monte Carlo simulation of triblock copolymer thin films

The morphologies of Am1B2nAm2 and AmBnCp triblock copolymer melt films confined between two hard walls are investigated via Monte Carlo simulations on simple cubic lattices. Depending upon the thickness of the film, parallel, perforated, mesh-like and normal lamellae can occur in A5B10A5 melts. Consequently, no sudden transition occurs between the parallel and normal lamellae. The ratio m1/m2 also affects the morphology of the Am1B2nAm2 melts. As the ratio is decreased, the microdomains become softer and the boundaries between different phases less sharp. In the AmBnCm systems, lamellar morphologies are present in a wide composition range, when the interaction energies between them and between each of them and vacancies (V) ϵAB=ϵAC=ϵBC=0.3, ϵAV=ϵBV=ϵCV=0, ϵAA=ϵBB=ϵCC=ϵVV=0 and the walls are neutral. By increasing the interactions between different kinds of segments from 0.3 to 1, major changes in morphology take place. The preference of the walls for various blocks greatly affects the morphologies and orientations of the microdomains.