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3D Printing of Bioinspired Capillary Transistors

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1 Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore, 639798, Singapore

* Corresponding Author: Kun Zhou. Email:

The International Conference on Computational & Experimental Engineering and Sciences 2024, 32(2), 1-1. https://doi.org/10.32604/icces.2024.013398

Abstract

Inspired by the unidirectional liquid spreading on Nepenthes peristome, Araucaria leaf, butterfly wings, etc., various microfluidic devices have been developed for water collection, irrigation, physical/chemical reaction, and oil–water separation [1-3]. Despite extensive progress, most natural and artificial structures fail to enhance the Laplace pressure difference or capillary force, thus suffering from a low unidirectional capillary height (< 30 mm). In this work, asymmetric re-entrant structures with long overhangs and connected forward/lateral microchannels are fabricated by three-dimensional (3D) printing, resulting in a significantly increased unidirectional capillary height of 102.3 mm for water, which approximately corresponds to the theoretical limit [4]. The overhangs can partially overlap the forward microchannels of the front structures without direct contact, thus enhancing the Laplace pressure difference and capillary force simultaneously. Based on the asymmetric and symmetric re-entrant structures, capillary transistors are proposed and designed to function as switches/valves and amplifiers/attenuators for microfluidic chips, enabling programmable adjustment of the capillary direction, height, and width in 3D space. As unprecedented open microfluidic devices, the capillary transistors provide a novel strategy for complex flow patterns and wetting, high-efficiency transpiration cooling, and advanced biochemical microreaction.

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Keywords

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