Selective Wetting And Adhesion On Micropillar Arrays Grafted With Thermoresponsive Polymer Brushes

Wetting and adhesion behavior of surface are of great importance for both fundamental materials research and practical applications. Several groups have exploited the use of adaptive polymers brushes and variable surface topography to dynamically tune the surface wetting behaviors 1-3 . However, Many questions remain as how microscopic and nanoscopic roughness (surface chemistry, morphology and geometry) contribute to surface wettability, how to efficiently and reversibly switch a surface from superhydrophobic to superhydrophilic, and on the basic nature of wetting transition. We have developed a new synthetic route that selectively grafts thermoresponsive polymer brushes, poly(N-isopropylacrylamide) (PNIPAAm), on well-defined, high-aspect-ratio micropillar arrays at different locations (either on tips only or everywhere), which allows for local control of the wetting behaviors. When the temperature was …