Liquid Transport in Bio-Inspired Capillary-Driven Open-Air Channels

Abstract

We fabricated a novel open-air channel with high efficient capillary-driven system inspired by a coastal animal “wharf roach”. The animal has open-air channels on its legs to transport water spontaneously using by capillary force. We abstracted principles controlling this phenomenon and applied it to artificial open-air channels, aiming at manipulating liquids without external energies. After surface modification for high surface free energy, the inspired open-air channels were able to transport water against gravity as well as the open-air channels of wharf roach by capillary effect of surface microstructures and chemistries. Topographical variation in micrometer-scaled patterns induced transport velocities improvement due to the enhancement of spreading intervals between the microstructure and wettability. Considering topography of micropatterned surfaces, the open-air channels with controllable transport velocity are applicable to capillary-driven microfluidics and lab-on-a-chips.