Light-Mediated Control of Interfacial Behavior for Thin-Film Block Copolymer Wetting

초록

In order to achieve spatial control of domain orientations in block copolymer thin films, we designed and synthesized a crosslinkable photosensitive random copolymer, namely poly(styrene-r-ortho-nitrobenzyl methacrylate-r-glycidyl methacrylate) (PSNG). A spin-coated thin film of the random copolymer was thermally crosslinked to create a light-sensitive surface. The extent of deprotection reaction of the onitrobenzyl group was effectively modulated by adjusting UV light energy irradiated to the crosslinked film. Accordingly, surface energy of the mat was tunable, further enabled the control of domain orientations in overlying lamellar or cylinder-forming poly(styrene-b-methyl methacrylate) thin films from perpendicular to parallel depending on UV light dosage. The results were further expanded to the use of photolithography to define the regions of the block copolymer domains with desired orientations.