Mechanically robust bio-based aerogel fibers encapsulated by PI for thermal insulation textile

Construct PI-encapsulated core-shell aerogel fibers to enhance mechanical robustness. • Achieve 29.4 MPa strength and 12.0 MJ·m −3 toughness in porous fibers. • Enable lightweight textiles with low thermal conductivity and flame retardancy. Bio-based aerogel fibers with ultrahigh porosity and low thermal conductivity are attractive candidates for sustainable thermal insulation textiles. However, their practical application is greatly limited by insufficient mechanical robustness. Here, we report a structurally engineered reinforcement strategy to fabricate mechanically robust aerogel fibers featuring a bacterial nanocellulose (BNC)/sodium alginate (SA) composite core encapsulated within a rigid polyimide (PI) shell. The treatment involves the formation of intertwined BNC aerogel frameworks (aerogel core) and the chemical imidization of poly(amic acid) (PAA) to form a robust PI shell. This design preserves the high porosity of the core while imparting exceptional mechanical robustness. The optimized P10t2.5 fibers exhibit a high tensile strength of 29.4 MPa, a high toughness of 12.0 MJ·m −3 , and excellent flame retardancy with an LOI of 33.5%. Textiles woven from P10t2.5 fibers exhibit an ultralow thermal conductivity of 0.033 W·m −1 ·K −1 . This work provides a viable route toward mechanically robust, thermally insulating aerogel textiles for personal thermal management in demanding environments.