Combinational biomimetic microfibers for high-efficiency water collection

Abstract

• Novel spinning method is developed for controllable generation of knotted microfibers. • Microfibers with single or combinational bionic structures are flexibly constructed. • Single biomimetic microfibers show superior water transport and hanging ability. • Combinational biomimetic microfibers reveal enhanced water collection efficiency. Collecting water from fog by microscale fibrous materials is a promising solution to the global water scarcity crisis. However, the previously designed fog harvesting microfibers solely imitate the characteristic structure of the wetted spider silk and have a limited water collection ability. To improve the water collection efficiency, we introduce a dynamic interfacial spinning (DIS) process to fabricate a novel type of fog harvesting microfibers that combine multiple biomimetic structures. Specifically, the DIS process utilizes a tunable vibration of the spinning nozzle at the air–liquid interface to facilitate the facile and controllable generation of the spider-silk-like microfibers consisting of periodic spindle knots and slender joints. Attributed to their distinct surface topography and unique geometric structure, the resultant microfibers have revealed a water transport velocity of 405 times more than that of natural spider silk and a water hanging ability of 4.7 times more than that of the previously reported knotted fibers. With parallel assembly of multiple spinning nozzles, the DIS process produces biomimetic microfibers that combine the water collection feature of the spider silk and the water transport feature of the cactus spine. The resultant microfibers have revealed a water collection efficiency of 1.74 times more than that of previously reported artificial spider silks. Our studies imply that the DIS method opens up an innovative way of constructing biomimetic microfibers for the improved fog harvesting performance.