Bioinspired Nanofibril-Humped Fibers with Strong Capillary Channels for Fog Capture

Bioinspired nanofibril-humped fibers (BNFs) are fabricated by using thermoplastic polyester elastomer and chitosan, via combining the electrospinning technique and fluid coating method to achieve periodic humps composed of interlaced random nanofibrils and a joint composed of aligned nanofibrils, which are highly similar to the micro/nanostructures of wetted spider silk. Especially, nanofibrils can increase the specific area of the hump to capture fog droplets effectively and transport water in channels between the nanofibrils under humid conditions, and thus the fog droplets can coalesce and be highly efficiently transported toward humps for water collection directionally. Such an ability of highly efficient fog capture is attributed to cooperation of an efficient transportation inside the outer shell of BNFs and outside transportation. Inside transportation is induced by anisotropic capillary channels between nanofibrils. When BNFs are wetted, the inside transportation mode is dominated for water collection, induced by anisotropic capillary channels between nanofibrils. BNF web is also used to investigate the droplet transportation in different cross-fiber contact modes in the process of fog capture on a large scale. This study offers an insight into the design of novel materials, which is expected to be developed for some realms of applications, such as fog harvesting engineering, filtration, and others.