Novel Complex Nanostructures from Directed Assembly of Block Copolymers on Incommensurate Surface Patterns.

Self-assembled nanostructures of block copolymer thin films have attracted enormous attention as useful templates for nanofabrication. We present that a chemically nanopatterned surface prepared by photolithography is able to direct the assembly of a block copolymer thin film to form a novel complex nanostructure. When a cylindrical block copolymer was assembled on a stripe pattern, whose pattern period was twice as large as a natural lattice size of the bulk nanostructure, a new structure was produced, where cylinders were alternately oriented parallel and perpendicularly to the surface. Self-consistent field calculations supported the emergence of the new structure, providing insight into the detailed structure and formation mechanism. Our work suggests that the combining top-down and bottom-up approaches may provide a versatile pathway for fabricating well-registered complex nanostructure, potentially useful in diverse advanced applications. References; S. O. Kim, et al. Nature 424, 411 (2003); M. P. Stoykovich, et al. Science 308, 1442 (2005); S. O. Kim, et al. Macromolecules 39, 5466 (2006); S. O. Kim, et al. Advanced Materials 19, 3271 (2007).