Bioinspired Coiled Composite Hydrogel Evaporator with Carbonized Hair for Efficient Solar Desalination and Salt Rejection.

Interfacial solar-driven seawater desalination has attracted significant attention. However, achieving both high evaporation rates and excellent salt resistance through advanced structural design and material optimization remains a considerable challenge. Inspired by coiled structures, this study presents a coil-structured solar evaporator (C-SPCH) fabricated by coiling a composite hydrogel containing carbonized hair, sodium alginate, and PVA (poly-(vinyl alcohol)). Its coiled architecture enables fast capillary channels and interconnected pores for enhanced water transport and salt tolerance. The irregular surface structure notably increases light-harvesting efficiency, while embedded hydrophilic groups smartly control water molecule states, cutting evaporation enthalpy. Therefore, the C-SPCH evaporator exhibits exceptional performance, achieving an evaporation rate of up to 5.36 kg·m-2·h-1 and an outstanding solar-vapor conversion efficiency of 150% (accounting for the additional environmental energy harvested by the three-dimensional coiled structure). It sustains efficient evaporation across a wide salinity range (0-25 wt %) and operates stably for 10 days in 15 wt % brine without significant performance degradation. This study offers insights into the structural design of solar-driven water evaporation systems, highlighting its significant potential for applications in both seawater desalination and high-salinity wastewater treatment.