화학공학소재연구정보센터
Applied Surface Science, Vol.349, 705-714, 2015
Microbumpers maintain superhydrophobicity of nano structured surfaces upon touch
Because of their fragility, nanostructured surfaces have not been used in applications that require mechanical contact with the environment. This paper demonstrates the utility of an array of "microbumpers" in the form of pillars rising above a nanostructured surface to provide protection. Superhydrophobic surfaces with micro-pillar arrays of varying pitch were fabricated and subjected to repeated vertical touch with a PDMS finger replica under different applied forces, such as would be experienced by a touch screen display. For sufficiently small pitches, the microbumpers maintained the strong water repellency and low droplet adhesion, even after 1000 touch cycles, but if the pitch was too large the nanostructures were damaged and the superhydrophobicity lost. In comparison, surfaces comprising only nano structures lost superhydrophobicity almost immediately. To image surface wetting by the water droplets, a droplet freeze-fixing, resin-embedding (FFRE) technique was developed. The approach of decorating a surface with microbumpers to provide mechanical protection should be applicable to a wide range of substrates with coatings optimized for various functions. (C) 2015 Elsevier B.V. All rights reserved.