Multiscale nanofiber-embedded aramid–polyimide composite yarns for antibacterial and thermal protective textiles

Firefighters working in high-temperature and physically demanding environments often experience sweat accumulation, which compromises wearing comfort and promotes microbial growth, creating a need for protective textiles with both reliable thermal protection and antibacterial functionality. However, conventional protective fabrics often fail to achieve antibacterial functionality while maintaining excellent flame-retardant and thermal-insulating performance, thereby limiting their overall protective efficiency. Herein, a multiscale nanofiber-embedded composite yarn was developed by using aramid 1313 and polyimide fibers as an intrinsically heat-resistant framework, followed by the electrospinning-assisted incorporation of triclosan-loaded polyacrylonitrile nanofibers in the staple-fiber yarn structure. The embedded nanofibers were designed to offer antibacterial functionality while maintaining the spinnability and weavability of the aramid and polyimide yarns. The composite yarn self-extinguished within 3 s after removal of the flame. Moreover, woven fabrics fabricated from the composite yarn generated a surface temperature difference of over 40°C compared with cotton fabrics when placed on a high-temperature hot plate, demonstrating superior thermal protective capability. In addition, the composite fabric showed favorable moisture-wicking performance and achieved antibacterial rates exceeding 99% against both Staphylococcus aureus and Escherichia coli . This work provides a feasible cross-scale nanofiber-embedding strategy for constructing multifunctional protective yarns and fabrics.