Fabrication of biomimetic gecko setae by direct photolithography and micromolding processes

In nature, geckos have developed complex adhesion structures capable of smart adhesion, the ability to cling to different smooth and rough surfaces, even ceilings, and detach at will. The hierarchical structure of gecko foot hair, consisting of microscale setae, branches and nanoscale spatula, contributes to the strong adhesion on different surfaces. In this paper, we present two approaches to fabricating high-aspect-ratio polymer fiber arrays mimicking gecko setae. SU-8 photoresist has been applied, and SU-8 fiber arrays with aspect ratio of 10 were obtained. Polydimethyl-siloxane (PDMS) microfiber arrays were fabricated through a micromolding process and the master template for this process was fabricated by using inductively coupled plasma (ICP) technology. The contact angle of water droplets on PDMS microfiber arrays shows increased hydrophobic property of PDMS microfiber arrays than non-patterned PDMS surface, from 102° to 137°.