Multi-biomimetic cellulose-based regenerated fibers from scalable wet spinning for ultrahigh-efficiency rate fog harvesting

Bioinspired fog harvesting materials offer a promising solution to freshwater scarcity. However, the integration of diverse biomimetic structures for ultrahigh fog harvesting collection rate remains challenging. This work presents a facile and scalable fabrication process for cellulose-based fog harvesting fiber (PSF) with multiple biomimetic features. The process involves wet spinning of cellulose and polyvinyl pyrrolidone (PVP), followed by dip-coating with cellulose and polyvinylidene fluoride (PVDF). Selective leaching of PVP can create microgrooves on fiber surface mimicking cactus spine structure, while dip-coating forms spindle knots and wettability gradients inspired by spider silk and Nepenthes pitcher. It is hypothesized that these bioinspired features enhance Laplace pressure differentials, wettability and curvature gradients, eventually facilitating the fog harvesting collection rate in terms of fog adsorption/capture, water film formation, droplet transport and shedding. Consequently, the resultant PSF achieves an exceptional fog collection rate of 180.62 g/cm 2 /h, 47 times higher than conventional spider silk. This study offers a novel insight and a scalable model for multi-biomimetic fog harvesting systems.