Polydopamine‐Wool Textiles for Sustainable Interfacial Solar Vapor Generation

ABSTRACT Interfacial solar vapor generation (ISVG), which harnesses sunlight for water distillation, presents a promising strategy to address global water scarcity. While conventional 3D evaporators offer high evaporation performance, their widespread implementation remains constrained by material selection, cost, and fabrication methods. Herein, we present a nature‐inspired, polydopamine (PDA)‐dyed wool textile as a 2.5D evaporator for ISVG, leveraging its double‐sided evaporating surfaces to maximize overall evaporation performance. The inherent fibrous architecture of wool textiles enables efficient water transport via natural capillary and exhibits effective solar absorption through photothermal PDA dyeing. The hierarchical nanostructure on micro‐scale fibers, created by subsequent plasma etching, further amplifies the light trapping and moisture wicking capabilities. Under 1‐Sun illumination, the PDA‐wool and ultrablack PDA‐wool textiles achieve evaporation rates of 2.21 and 2.43 kg/m 2 /h, respectively. In modeled calculations, both outperform the commercial baseline, with ultrablack‐wool exceling in low‐solar regions. The all‐natural composition eliminates concerns regarding the leaching of microplastics or hazardous nanomaterials. Furthermore, the system maintains a stable evaporation rate for 10 h of continuous operation without salt‐accumulation. This approach opens new opportunities for natural textiles and offers a cost‐effective route toward deployment of textile‐based solar‐driven water purification systems with strong practical viability in off‐grid and socially vulnerable communities.