Hydrophobic, flexible, and flame-retardant sodium alginate/guar gum-based porous yarns for personal thermal management

Low-density, high-porosity porous fibers have garnered significant attention for the fabrication of wearable thermal management materials. However, the practical application of sodium alginate (SA) porous fibers is hindered by their inherent hydrophilicity, inadequate flexibility, and poor weavability. In this study, guar gum (GG) and boric acid (BA) were incorporated into SA via a directed freezing wet-spinning strategy, resulting in the formation of a multi-crosslinked network structure. Porous fibers with a porosity of up to 93.6 % were successfully fabricated. Furthermore, a hydrophobic surface layer composed of polymethylsilsesquioxane (PMSQ)-modified silica microspheres was constructed. The resulting material exhibits outstanding hydrophobicity (water contact angle of 139.22°), as well as exceptional flame retardancy, achieving a limiting oxygen index of 47.63 % (UL-94V-0 rating). Importantly, the high porosity contributes to a low thermal conductivity of 0.037 W·m −1 ·K −1 , endowing the fabric with superior thermal insulation performance. The developed H-SA/GG/BA 0.4 fabric demonstrated temperature differentials of 10.2 °C on a high-temperature stage (75 °C) and 9.6 °C on a low-temperature stage (−20 °C), substantially outperforming conventional textiles such as cotton and polyester.