Ambient-pressure-dried aramid aerogel fibers with carbon nanotube crosslinking for integrated thermal insulation and solar heating abilities

Abstract

Aerogel fibers, exhibiting distinct porous architecture and fiber flexibility, have emerged as leading materials for personal thermal protection applications; however, the complex drying process and singular thermal insulation mechanism limit their use in complex environments. In this work, aramid nanofiber/carbon nanotube (ANF/CNT) aerogel fibers, integrating passive thermal insulation and active solar heating, were prepared by wet-spinning and ambient-pressure drying (APD). The incorporation of CNT and Ca²⁺ into ANF aerogel fibers generates abundant physical and chemical crosslinking points, strengthening the nanofiber network’s skeleton, and thereby reducing the structural collapse during APD with only 8.9% shrinkage. Thus, the synthesized ANF/CNT aerogel textiles demonstrated low thermal conductivity (33.8–40.4 mW/(m K)) and thermal insulation ability from −196 to 400 °C. More importantly, the photothermal effect of CNT enables active solar heating of aerogel fibers, effectively supplementing their thermal insulation, and allowing them to withstand extremely cold environments. In real tests, the synergistic effect of passive insulation and active heating improved the skin temperature by up to 5.9 °C, much higher than 1.6 °C obtained solely for passive insulation. Therefore, the ANF/CNT aerogel fibers exhibit promising potential for smart, controllable personal thermal management applications by combining their flexibility, mechanical strength, and flame retardancy.