For millennia, human thermal apparel has relied on natural fibers (such as wool, down, and cotton) or synthetic polymer yarns (such as polyester and acrylic). The physical principle underlying these traditional textiles is the entrapment of stagnant air within fiber matrices to inhibit heat transfer. However, conventional textiles face performance limits under severe environments, including polar expeditions, high-altitude aviation, and space exploration: attaining necessary thermal resistance requires heavy bulk, while moisture ingress, mechanical compression, or wind penetration drastically degrades insulating capability.

Bridging the thermal insulation of aerogels with the flexibility, strain tolerance, and drapability of traditional fibers represents a priority in smart textile research. Bulk silica aerogels are notoriously brittle, failing under mechanical bending or tension, which precludes direct textile integration. To address this limitation, research teams pioneered scalable manufacturing methods for continuous aerogel fibers. Leveraging microfluidic spinning or wet spinning techniques, structural polymers (such as aramid, cellulose, or silk fibroin) or graphene are cross-linked with aerogel precursors, yielding continuous flexible filaments that retain nanoscale porosity alongside micron-scale fiber diameters.

These aerogel fibers demonstrate thermal conductivities well below those of high-loft goose down (reaching down to 0.015 W/m·K) while maintaining mechanical compliance. Consequently, they can be processed via industrial spinning, weaving, knitting, and laundering workflows. Thermal garments woven from aerogel yarns achieve equivalent or superior thermal protection at a fraction of the thickness of traditional outerwear, maintaining performance down to -40°C and eliminating the bulkiness historically associated with extreme cold-weather gear.

Furthermore, aerogel fibers enable new functionality within smart wearable platforms. By encapsulating phase-change materials (PCMs), conductive polymers (e.g., PEDOT:PSS), or liquid metals within or upon the aerogel fiber network, textiles acquire electrothermal heating and active thermal regulation capabilities. Integrated with flexible photovoltaics, aerogel electrothermal yarns provide rapid Joule heating under minimal drive voltages, while the thermal isolation of the porous matrix retains generated heat adjacent to the skin. Combining thermal insulation, low mass, mechanical compliance, and electronic functionality, aerogel smart textiles are advancing personal thermal management (PTM) and specialized protective apparel.