Bending soft block copolymer nanostructures by lithographically directed assembly

The creation of several patterns with different curvatures within the same block copolymer thin films which conform to patterns with radii of curvature equal to the equilibrium domain spacing, was investigated. Hydroxyl-terminated polystyrene (PS-OH) with number-averaged molecular weight, M n= 5.1kg/mol was synthesized using standard anionic polymerization techniques. A 40 nm film of PS-OH was applied to the oxide coating of a piranha-cleaned silicon wafer by spin-coating from a toluene solution. The results show that the lithographically directed assembly of block copolymers can be successfully applied even if the desired patterns are very different from the equilibrium morphology.