Controllable Strong and Ultralight Aramid Nanofiber-Based Aerogel Fibers for Thermal Insulation Applications

High-performance polymer-based aerogel fibers with ultrahigh porosity, mechanical robustness and outstanding thermal stability are demanded for applying in effective thermal insulation devices, especially in harsh environment. However, the poor mechanical properties and thermal stability of the commonly reported polymer-based aerogel fibers restricted their applications in many areas. As a special nano-build-block, aramid nanofiber-based aerogel fiber is expected to conquer this problem in virtue of the outstanding performance, intrinsically related to aramid fibers. Herein, a series of aramid nanofiber-based aerogel fibers were fabricated via a facial wet-spinning method combined with freeze–drying technique. The effects of coagulation bath temperature and the solid contents of the spinning precursors on their morphologies and mechanical properties were systematically studied. The obtained aerogel fibers possessed high porosity (> 92%), good mechanical properties (tensile strength ~ 8.1 MPa) and high specific surface area (~ 239 m2/g). Meanwhile, the woven textiles exhibited a low thermal conductivity (~ 34 mW/(m·K)) and outstanding thermal insulation properties under a wide range of temperature. In addition, surface modification by Teflon resin could make the ANAFs hydrophobic, thus exhibiting their applicational prospects in a humid environment. Overall, the aramid nanofiber-based aerogel fibers and their textile throw light in a favorable direction for developing high-performance thermal insulation fibers and textiles.Graphical AbstractAramid nanofiber-based aerogel fibers with high porosity (> 92%), good mechanical properties (tensile strength ~ 8.1 MPa) and high specific surface area (~ 239 m2/g) are fabricated by a novel and facial strategy including wet-spinning, solvent replacement and freeze–drying processes. Meanwhile, the weaved textiles exhibit a low thermal conductivity (~ 34 mW/(m·K)) and outstanding thermal insulation properties under a wide range of temperatures.