Zhenhai Xia

Abstract:

Geckos have the extraordinary ability to keep their sticky feet from fouling while running on dusty walls and ceilings. Understanding gecko adhesion and self-cleaning mechanisms is essential for elucidating animal behaviors and rationally designing gecko-inspired devices. We report a unique self-cleaning mechanism possessed by the nano-pads of gecko spatulae in both dry and wet conditions. This study has provided direct evidence that the unique shape of nanoscale spatula pads plays a crucial role in generating robust and stable adhesion while permitting efficient self-cleaning capabilities in dynamic regimes. Inspired by this natural design, we have fabricated micro/nano-pad-terminated artificial spatulae and micromanipulators that show similar effects, and that provide a new way to manipulate microparticles in dry and aqueous environments. By simply tuning the pull-off velocity, our gecko-inspired micromanipulators, made of synthetic microfibers with graphene-decorated micro-pads, can easily pick up, transport, and drop off microparticles for precise assembling. This work should open the door to the development of novel highly-efficient biomimetic self-cleaning adhesives, smart surfaces, MEMS, tunable micro/nano-manipulators, biomedical devices, and more.