RESUMEN
Firefighting clothing is an indispensable protective equipment for firefighters performing rescue activities under extreme heat and fire conditions. However, few bio-based thermal management materials that provide thermal comfort to firefighters in different operational scenarios have been reported. Herein, we present a novel strategy to prepare Janus-type aerogels based on sodium alginate biological macromolecules, consisting of a SiO2 nanoparticle layer and a microencapsulated paraffin@SiO2 phase-change composite layer. A passive radiative cooling and thermal energy storage was integrated into a functional dual-mode material system. Results show that Janus-type aerogel to cool down by 11.5 °C on a hot summer day. Meanwhile, paraffin@SiO2 has a high melting enthalpy of 127.5 J g-1 that effectively buffers temperature rise during the phase-change process. This Janus-type aerogel has ultra-low heat insulation (0.042 W/(m·K)), it can delay approximately 76.6 s to reach second-degree burn time for skin at a radiant heat exposure of 18.4 kW m-2. The work provides an innovative way to develop bio-based thermal management materials, which could enable multi-scenario thermal management for firefighting clothing.
RESUMEN
Firefighting protective clothing is a crucial protective equipment for firefighters to minimize skin burn and ensure safety firefighting operation and rescue mission. A recent increasing concern is to develop self-powered fire warning materials that can be incorporated into the firefighting clothing to achieve active fire protection for firefighters before the protective clothing catches fire on fireground. However, it is still a challenge to facilely design and manufacture thermoelectric (TE) textile (TET)-based fire warning electronics with dynamic surface conformability and breathability. Here, we develop an alternate coaxial wet-spinning strategy to continuously produce alternating p/n-type TE aerogel fibers involving n-type Ti3C2Tx MXene and p-type MXene/SWCNT-COOH as core materials, and tough aramid nanofiber as protective shell, which simultaneously ensure the flexibility and high-efficiency TE power generation. With such alternating p/n-type TE fibers, TET-based self-powered fire warning sensors with high mechanical stability and wearability are successfully fabricated through stitching the alternating p-n segment TE fibers into aramid fabric. The results indicate that TET-based fire warning electronics containing 50 p-n pairs produce the open-circuit voltage of 7.5 mV with a power density of 119.79 nW cm-2 at a temperature difference of 300 °C. The output voltage signal is then calculated as corresponding surface temperature of firefighting clothing based on a linear relationship between TE voltage and temperature. The fire alarm response time and flame-retardant properties are further displayed. Such self-powered fire warning electronics are true textiles that offer breathability and compatibility with body movement, demonstrating their potential application in firefighting clothing.
