Perpendicular Domain Orientation in Dense Planar Brushes of Diblock Copolymers

Abstract

Dense planar brushes of diblock copolymers physically attached to the substrate by end groups are studied by the dissipative particle dynamics simulation technique. We predict stability of spatially ordered perpendicularly oriented domains which are separated from the substrate and the free surface of the film by homogeneous layers of different type. Depending on composition of the copolymer, various structures including hexagonally ordered “golf holes”, parallel “gullies” and “ridges”, and “stalactites” ordered with the symmetry of hexagonal lattice can be stable. We analyze regimes of good and poor solvents for both blocks (nonselective solvents). Physical reasons for perpendicular domain orientation are discussed. In the case of low “grafting” density, our results coincide with those reported in the literature.