title: Enhanced Wettability Changes by Synergistic Effect of Micro/Nanoimprinted Substrates and Grafted Thermoresponsive Polymer Brushes.
abstract: Thermoresponsive polymer brushes are grafted on micro/nanostructured polymer substrates as new intelligent interfaces that synergistically enhance wettability changes in response to external temperature stimuli. Thermoplastic poly(styrene-co-4-vinylbenzyl chloride) [P(St-co-VBC)] is synthesized using radical polymerization and spin-coated on a glass substrate. Micro/nanopillar and hole patterns are imprinted on the P(St-co-VBC) layer using thermal nanoimprint lithography. Poly(N-isopropylacrylamide) (PIPAAm) brushes are grafted on the micro/nanostructured P(St-co-VBC) layer through surface-initiated atom-transfer radical polymerization using 4-vinylbenzyl chloride as the initiator. The imprinted micro/nanostructures and grafted PIPAAm brush chain lengths affect the surface wettability. Combinations of nanopillars or nanoholes (diameter 500 nm) and longer PIPAAm brushes enhance hydrophobic/hydrophilic changes in response to temperature changes, compared with the flat substrate. The thermoresponsive hydrophobic/hydrophilic transition is synergistically enhanced by the nanostructured surface changing from Cassie-Baxter to Wenzel states. This PIPAAm-brush-modified micro/nanostructured P(St-co-VBC) is a new intelligent interface that effectively changes wettability in response to external temperature changes.
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University (TWIns), 8-1 Kawadacho, Shinjuku, Tokyo, 162-8666, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nagase
authors.affiliation: Department of Life Science and Medical Bioscience Graduate, School of Advanced Science and Engineering, Waseda University (TWIns), 2-2 Wakamatsucho, Shinjuku, Tokyo, 162-8480, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Onuma
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University (TWIns), 8-1 Kawadacho, Shinjuku, Tokyo, 162-8666, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamato
authors.affiliation: Department of Life Science and Medical Bioscience Graduate, School of Advanced Science and Engineering, Waseda University (TWIns), 2-2 Wakamatsucho, Shinjuku, Tokyo, 162-8480, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Takeda
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University (TWIns), 8-1 Kawadacho, Shinjuku, Tokyo, 162-8666, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D054802:Molecular Imprinting; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D058105:Polymerization; D011137:Polystyrenes / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D017155:Wettability
chemical_list: D000180:Acrylic Resins; D011137:Polystyrenes; C052970:poly-N-isopropylacrylamide
keywords: contact angles; intelligent interfaces; nanoimprint lithography; polymer brushes; thermoresponsive