Gradient functionalized strategy towards flame-retardant and strong bacterial cellulose aerogel fibers for fire...

Traditional fibers such as polyester and polyacrylonitrile are increasingly unable to meet the growing demands of indoor textiles for sustainability, thermal insulation, flame retardance, and early fire warning. This work proposes a gradient functionalized strategy to prepare highly multifunctional bacterial cellulose aerogel fibers through sequentially constructing a flame-retardant layer, a sensing layer, and a hydrophobic layer onto fiber surface. Moreover, synergistic effects can be exerted among the functional layers. The as-prepared fibers exhibit the outstanding flame-retardant properties and an ultra-high mechanical strength of 73.2 MPa. In addition, the aerogel fibers have an ultralow density of only 0.12 g·cm^-3 and a thermal conductivity as low as 0.058 W·m^-1·K^-1. The thermal insulation performance is far superior to those of traditional fibers including polyester, polyamide, and cotton. More importantly, the aerogel fibers demonstrate an exceptional fire-sensing capability, which could detect the flames and then trigger an alarm within 1 s. This study provides a novel strategy for the design and preparation of highly multifunctional and sustainable aerogel fibers for indoor textiles.