Binary blends of diblock copolymers as an effective route to multiple length scales in perfect directed self-assembly of diblock copolymer thin films

The directed assembly of binary blends of diblock copolymers on chemically nanopatterned substrates was investigated as a means to pattern features of controlled dimensions at the nanoscale. The lamella-forming blends assembled without defects and in registration with underlying chemical surface patterns that had periods LS that were commensurate with the bulk lamellar period of the blends LB. LB was tuned between the bulk lamellar periods of the block copolymers LO1 and LO2.