Enhanced capillary pumping through evaporation assisted leaf-mimicking micropumps

TL;DR

This paper introduces a leaf-mimicking micropump that significantly enhances fluid delivery efficiency through evaporation-assisted capillary action, offering a scalable and inexpensive design for microfluidic applications.

Contribution

The work presents a novel, bio-inspired micropump design that achieves a sixfold increase in pumping rate by mimicking leaf microstructures, with simple fabrication and improved performance.

Findings

Achieved ~6 times higher volumetric pumping rate.

Demonstrated effective pressure head sustainence.

Validated design through SEM characterization and experimental testing.

Abstract

Pumping fluids without an aid of an external power source are desirable in a number of applications ranging from a cooling of microelectronic circuits to Micro Total Analysis Systems (micro-TAS). Although, several microfluidic pumps exist, yet passive micropumps demonstrate better energy efficiency while providing a better control over a pumping rate and its operation. The fluid pumping rate and their easy maneuverability are critical in some applications; therefore, in the current work, we have developed a leaf-mimicking micropump that demonstrated ~6 fold increase in a volumetric pumping rate as compared to the micropumps having a single capillary fluid delivery system. We have discussed a simple, scalable, yet inexpensive method to design and fabricate these leaf mimicking micopump. The microstructure of the micropumps were characterised through scanning electron microscopy and its pumping performance (volumetric pumping rate and pressure head sustainence) were assessed experimentally. The working principle of the proposed micropump is attributed to its structural elements; where branched-shaped microchannels deliver the fluid acting like veins of leaves while the connected microporous support resembles mesophyll cells matrix that instantaneously transfers the delivered fluid by a capillary action to multiple pores mimicking the stomata for evaporation. Such design of micropumps will enable an efficient delivery of the desired volume of a fluid to any 2D/3D micro/nanofluidic devices used in an engineering and biological applications.