Bio-inspired slanted polymer nanohairs for anisotropic wetting and directional dry adhesion

Slanted polymer nanohairs possess a number of attractive properties in terms of anisotropic wetting and directional adhesion. This highlight provides an overview of the recent progress in the development of bio-inspired slanted polymer nanohairs and their applications towards anisotropic wetting and directional dry adhesion properties. With the advanced nano-fabrication techniques, it is possible to fabricate angled, directionally bent polymer nanohairs in a highly reproducible and geometry-controllable manner. The fabrication methods can be categorized into two streams: direct replica molding from a master with slanted structure or nanofabrication (photolithography or molding) with post treatment such as e-beam exposure, thermal annealing and mechanical compression. In this highlight, the fabrication methods for angled, high aspect ratio polymer nanohairs are briefly described along with their potential applications in anisotropic wetting and directional adhesion. Particular emphasis is given to recent achievements and future directions in biomimetic functional surfaces.