Diblock copolymer thin film melts on striped, heterogeneous surfaces: Parallel, perpendicular and mixed lamellar morphologies

We consider the problem of a diblock copolymer melt thin film on a striped surface. Because of the different surface energies, the different stripes h ave different preferences for each of the blocks, while the upper free surf ace may also prefer one of the blocks. As a result of a combination of fact ors such as the surface tensions and chain stretching, a number of morpholo gies may appear. We allow for perpendicular, parallel, and mixed type lamel lae and study the resulting phase diagrams. These diagrams should provide a crude guide for experimental studies on such systems. Our main conclusions are a-fold. First the phase diagram is intricate and complicated. Second, to produce a single crystal oriented along the stripes, it is best to use t hin films and a diblock lamellar size equal to or larger than the stripe wi dth.