title: Polarity-switching top coats enable orientation of sub-10-nm block copolymer domains.
abstract: Block copolymers (BCPs) must necessarily have high interaction parameters (χ), a fundamental measure of block incompatibility, to self-assemble into sub-10-nanometer features. Unfortunately, a high χ often results from blocks that have disparate interfacial energies, which makes the formation of useful thin-film domain orientations challenging. To mitigate interfacial forces, polymers composed of maleic anhydride and two other components have been designed as top coats that can be spin-coated from basic aqueous solution in the ring-opened, acid salt form. When baked, the anhydride reforms and switches polarity to create a neutral layer enabling BCP feature alignment not possible by thermal annealing alone. Top coats were applied to the lamella-forming block copolymers poly(styrene-block-trimethylsilylstyrene-block-styrene) and poly(trimethylsilylstyrene-block-lactide), which were thermally annealed to produce perpendicular features with linewidths of 15 and 9 nanometers, respectively.
authors.affiliation: Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Bates
authors.forename: Takehiro
authors.initials: T
authors.lastname: Seshimo
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Maher
authors.forename: William J
authors.initials: WJ
authors.lastname: Durand
authors.forename: Julia D
authors.initials: JD
authors.lastname: Cushen
authors.forename: Leon M
authors.initials: LM
authors.lastname: Dean
authors.forename: Gregory
authors.initials: G
authors.lastname: Blachut
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ellison
authors.forename: C Grant
authors.initials: CG
authors.lastname: Willson