Liquid Shuttle Mediated by Microwick for Open-Air Microfluidics

摘要

Microfluidics has experienced rapid progress in additive manufacturing andmicrofluidic soft robots. The design of microfluidics is already moving into amore intelligent, integrated, and detachable direction. However, the pipelineresistance needs more external energy input to achieve high flow speed.Guided transport of liquid in the open-air-space microfluidics will be an effectivesolution. Inspired by the water shuttle on the pitcher plant tendril, herein,an open-air microfluidic transport device is designed that consists of a superhydrophilicmicrowick with multi-microgrooves by stereolithography. Theliquid film confined in microgrooves can promote rapid fluid shuttle on thewet surface to enhance transport rate and inhibit the Rayleigh-Plateau instabilityfrom forming larger dripping drops. The dripping volume and thresholdCapillary number are optimized for effective liquid transport and drainage.State-of-the-art microwick liquid shuttle technologies can guide liquid continuouslyin a prescribed direction or into multiple directions with 98 transportefficiency (the ratio of liquid collection volume and liquid injection volume)for water and 97 for ethanol in the closed-open-closed space. The proposedmechanism has the potential to streamline microfluidic applications-and,therefore, accelerate relevant liquid delivery development and ultimately theirapplications in microfluidic chip and additive manufacturing.