Ultra-strong skin-core polymer aerogel fibers via wet-freeze spinning

Abstract

Aerogel fibers, as synthetic fibers with a three-dimensional (3D) porous structure, outperform traditional fibers in thermal management. However, they still face the challenge of balancing mechanical properties and thermal insulation to fully realize their potential. Here, we report a wet-freeze spinning technique for the continuous, large-scale preparation of dense skin-porous core-structured polyimide aerogel fibers. The unique multiscale structural design, which includes a highly oriented dense skin layer to withstand load stresses and a porous core to impede heat transfer, achieves exceptionally high strength and low thermal conductivity. The resulting robust skin-core polyimide (SCPI) aerogel fibers exhibit ultrahigh specific strength up to 775.8 MPa cm³ g⁻¹, much higher than previously reported aerogel fibers. Moreover, the obtained aerogel fabrics demonstrate excellent thermal insulation properties (30.4 mW m⁻¹ K⁻¹) under long-term thermal shock. This strategy offers a universal and continuous way to prepare high-strength aerogel fibers and is crucial for promoting the fiber industry.