Solvent-induced transition from micelles in solution to cylindrical microdomains in diblock copolymer thin films

Abstract

It is well-known that block copolymer thin films can be easily prepared on different substrates by spin coating. Here, we show that the cylindrical microdomains of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) copolymers can be oriented normal to the surface over a large area by spin coating in toluene/THF solvent mixture. The structure and size of the PS-b-P4VP in solution were compared with those in thin films. It was found that the cylindrical microdomains, obtained by spin coating, oriented normal to the film surface depended strongly on the amount of THF in the casting solution. The study was extended to PS-b-P4VP copolymers with different molecular weights and compositions, which allowed the control of the size of the cylindrical domains and the areal density of the arrays