title: (Photo-)thermally induced formation of dynamic surface topographies in polymer hydrogel networks.
abstract: In this Article, we report on our approaches to creating responsive hydrogel coatings with surfaces that can be switched between a close to flat state and a state with a predesigned topographic pattern. The trigger is either temperature or, indirectly, light. The hydrogel coatings are based on the known thermal responsive poly(N-isopropylacrylamide) utilizing its solubility change at its lower critical solution temperature (LCST) at around 32 °C. Using this material in combination with controlled cross-linking, we developed three fabrication strategies. Thermally switching symmetric surface topographies were created by careful and spatial control of the cross-link density. Sensitivity to light was created by patterns of tin oxide converting absorbed light into local heat. And to broaden the application range, we introduced a method based on volumetric effects created by a corrugated substrate. The latter method allows for the formation of asymmetric or slanted surface structures.
authors.affiliation: Department of Functional Organic Materials and Devices, Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands. d.liu1@tue.nl
authors.forename: Danqing
authors.initials: D
authors.lastname: Liu
authors.forename: Cees W M
authors.initials: CW
authors.lastname: Bastiaansen
authors.forename: Jaap M J
authors.initials: JM
authors.lastname: den Toonder
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Broer
mesh_terms: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D055668:Photochemical Processes; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D013696:Temperature
chemical_list: D011108:Polymers; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate