Photothermal Fabrics Based on Biomimetic Mineralization of Natural Collagen Fiber Network for Thermal Management in Cold Environments

Photothermal fabrics with efficient warmth retention and energy savings have attracted widespread attention in thermal management. However, surface icing, which deteriorates photothermal performance, still limits their practical application in extremely cold environments. Herein, a tannic acid (TA)-mediated biomimetic mineralization strategy is proposed to achieve stable and dense loading of Fe₃O₄ nanoparticles onto a natural collagen fiber network (CFN), yielding a photothermal fabric (TA-Fe@CFN, TFC) with excellent mechanical strength as well as high air and water-vapor permeability. Benefiting from the natural hierarchical porous structure of the CFN that enhances broadband light absorption, TFC achieves a solar absorptance of 96.9% and exhibits superior photothermal performance compared with ordinary black cotton fabric (BCF). Moreover, the mineralized TFC shows outstanding anti-icing performance, as its hydrophobic surface resulting from the dense immobilization of Fe₃O₄ nanoparticles on collagen fibers delays droplet freezing for 1080 s and enables the fabric to rapidly return to 26.5 °C after photothermal deicing on a -15 °C cold platform. Furthermore, the Fe₃O₄ mineralized layer significantly enhances the flame retardancy of the CFN, raising the limiting oxygen index of TFC to 36% and thereby improving the safety of the fabric in use. In terms of practicality, the developed photothermal TFC also exhibits excellent ultraviolet (UV) protection (UPF > 2000) and aging resistance, ensuring durable outdoor performance. This work provides new insights into the design of multifunctional, high-performance photothermal fabrics for thermal management in complex cold environments.