The self-assembly of asymmetric block copolymers in films contacting a patterned surface

Abstract

The preparation of ordered high-density polymer layers via the combined method of templated self-assembly is discussed. This approach combines the advantages of guided self-assembly of block copolymers and lithography on a topographical or chemical pattern. To implement the approach, a simulation has conducted for the first time through the use of the dissipative particle dynamics method in the NPAT ensemble. The pattern replication by asymmetric copolymers that form cylindrical phases in the bulk owing to their self-assembly near the patterned surface is studied. The effects of three patterns are described, i.e., hexagonal, rectangular, and triangular, which are characterized by one or two length scales. It is shown that the dense hexagonal pattern and the sparse rectangular and triangular patterns induce vertically oriented cylindrical domains in a thin film. The control of the orientation and ordering in the formed morphology heavily depends on the interaction between the minority component and the pattern. This effect is global in nature: The surface pattern propagates into the bulk of a film. In the case of rectangular and triangular patterns, two- and fourfold increases in their quantitites in the bulk are observed.