Steering capillary flow in textiles is of great significance in developing affordable and portable microfluidics devices. However, owing to the complex fibrous network, it remains a great challenge to achieve capillary flows with precise filling fronts. Here, an in situ laser engraving route is reported to accurately and rapidly etch textiles for manipulating capillary flow. The heterogeneity of the textile structure is enhanced because of the directional spreading of molten fibers polymer under the control of surface energy minimization. The principle of achieved anisotropic wicking of a water droplet in laser-engraved textiles is proposed. This understanding enables patterning the filling front of a fluid in different shapes, including arrow, straight line, diamond, and annulus. Precise capillary flow in textile-based microfluidics can benefit application in many fields, such as chemical analysis, biological detection, materials synthesis, multiliquid delivery. The laser engraving strategy has the advantages of simplicity, full scalability, and time rapidity, which provides an efficient avenue to steer capillary flow in diverse textiles for manufacturing customized microfluidic devices.
Keywords: capillary flow; laser engraving; microreaction; oil−water separation; textile-based microfluidics.