Producing Small Domain Features Using Miktoarm Block Copolymers with Large Interaction Parameters.

We demonstrate that small domain features (∼13 nm) can be obtained in a series of polystyrene (PS) and poly(lactic acid) (PLA) block copolymers, PS-(PLA)2 and (PS)2-(PLA)2, that combine miktoarm molecular architectures with large interaction parameters. To supplement the experimental work, we used self-consistent field theory in tandem with the random phase approximation to explore and contrast the phase behavior of ABn and AnBn types of miktoarm block copolymers. Specifically, AB2 and A2B2 were found to be effective molecular architectures for inducing strong shifts in phase boundaries with copolymer composition and to simultaneously tune domain feature sizes. The performance of these systems is markedly different from the corresponding linear diblock copolymers and indicates the potential of macromolecular architecture control for future applications in lithography.