Molecular aggregation states and wetting behavior of a poly{2-(perfluorooctyl)ethyl acrylate} brush-immobilized nano-imprinted surface

Abstract

Topologically ordered surfaces with a polymer brush-grafted layer were prepared by a combination of nano-imprinting (NI) and surface-initiated atom transfer radical polymerization (SI-ATRP). The molecular aggregation state and the wetting were evaluated by synchrotron radiation X-ray analyses and water droplet contact angle measurements, respectively. An ordered topography was fabricated onto a spin coated thin film of a polymethacrylate-based copolymer with polymerization initiating sites [P(MMA-co-BIEM)] by NI. Then poly{2-(perfluorooctyl)ethyl acrylate} (PFA-C8) chains were grafted onto the thin film by SI-ATRP. The surface geometry was maintained after PFA-C8 grafting when the thickness of the grafted polymer layer was sufficiently thin to a scale of the concave region. The modified P(MMA-co-BIEM) thin film surface was water repellent by a synergetic effect of the surface geometry and the low surface free energy of the grafted PFA-C8 layer.