Biomimetic inner helicoidal microfluidics with enhanced capillary rise for step liquid lifting mimicking transpiration

Bionic microfluidics is garnering increasing attention due to the superior fluidic performance enabled by biomimetic microstructures. Inspired by the unique structures of young pumpkin stems, we fabricate helicoidally patterned microchannels with precisely controlled morphologies using the projection micro-stereolithography (PμSL)-based 3D printing technique. Our helicoidally patterned microchannels achieve approximately twice the liquid lifting height compared to similarly sized smooth microchannels. This improvement is attributed to the enhanced capillary force. The additional meniscus formed between the helicoidally patterned microstructures significantly contributes to the increased capillary effects. Furthermore, the underlying mechanisms of fluidic performance in helicoidally patterned microchannels are theorized using a newly developed equation, which is also employed to optimize the geometric parameters and fluidic performance of the biomimetic helicoidal microchannels. Additionally, our biomimetic helicoidally patterned microchannels facilitate a significant step-lifting phenomenon, mimicking tall trees’ transpiration. The fluidic performance of our biomimetic helicoidally patterned microchannels show promise for applications in enhanced liquid lifting, step-lifting, clean-water production, and others.