Biomimetic Design of Capillary-Driven Photothermal Fabric for Efficient Interface Evaporation.

Abstract

Solar vapor generation (SVG) offers a promising solution to freshwater scarcity; however, current solar evaporators suffer from limitations in water transport, salt resistance, and scalability, hindering their commercial application. To address these challenges, this study introduces a biomimetic capillary-driven photothermal fabric. Using sodium alginate (SA) as the matrix, vinyl silicon-based nanoparticles (VSNP) and reduced graphene oxide (rGO) are integrated to form a multi-hybrid structure with interconnected flexible dynamic hydrogen bonds and rigid ionic cross-links. This configuration imparts the fibers with high strength (2.972 cN/dtex) and toughness (8.856% elongation at break). The alginate-based fabric, produced via wet spinning and weaving, retains outstanding mechanical and structural stability. Inspired by plant water transport mechanisms, the photothermal fabric efficiently channels water to the evaporation interface through its porous structure and capillary action. The rGO's π-π conjugation enhances the fabric's light absorption and photothermal conversion. Under 1 kW m^-2 solar irradiation, the fabric's surface temperature reaches 118.5 °C, with an evaporation rate of 2.886 kg m^-2 h^-1, 6.87 times higher than pure water, and an evaporation efficiency of 118.95%. Additionally, the fabric exhibits excellent salt resistance, stable cyclic performance, and scalability for mass production, offering new potential for solar-driven evaporation technologies.