Ultralight and Superelastic Curly Micro/Nanofibrous Aerogels by Direct Electrospinning Enable High‐Performance Warmth Retention

Abstract Extremely low temperature has posed huge burden on the public safety concerns and global economics, thereby calling for high‐performance warmth retention materials to resist harsh environment. However, most present fibrous warmth retention materials are limited by their large fiber diameter and simple stacking structure, leading to heavy weight, weak mechanical property, and limited thermal insulation performance. Herein, an ultralight and mechanically robust polystyrene/polyurethane fibrous aerogel by direct electrospinning for warmth retention is reported. Manipulation of charge density and phase separation of charged jet allows for the direct assembly of fibrous aerogels consisting of interweaved curly wrinkled micro/nanofibers. The resultant curly wrinkled micro/nanofibrous aerogel possesses low density of 6.8 mg cm −3 and nearly full recovery from 1500‐cycle deformations, exhibiting both ultralight feature and superelastic property. The aerogel also shows low thermal conductivity of 24.5 mW m −1 K −1 , making synthetic warmth retention materials superior to down feather possible. This work may shed light on developing versatile 3D micro/nanofibrous materials for environmental, biological, and energy applications.