Fast Preparation of Ultratough Cellulose Aerogel Fibers via One-Step Composite Solvent Exchange under Ambient Pressure Drying

Abstract Traditional ambient-pressure drying of aerogels relies on minimizing capillary shrinkage to preserve nanoporous structures, yet this strategy inevitably compromises either processing efficiency or mechanical robustness. Here, we show that capillary shrinkage can instead be exploited as a controllable structural reconstruction process. Through a rapid composite solvent exchange strategy, effective solvent exchange is achieved within only 10 min, enabling regulated capillary stress to drive network rearrangement and pore-wall reinforcement during ambient-pressure drying while preserving an interconnected nanoporous architecture. The resulting cellulose aerogel fibers exhibit a density of 0.10 g·cm–3, an areal porosity of 82.15%, and a specific surface area of 90.67 m2·g–1, together with a tensile strength of 29.46 MPa and a toughness of 10.05 MJ·m–3, representing strength improvements of 135.1% and 280.6% over freeze-dried and supercritical-dried counterparts, respectively. Despite moderate network densification, the aerogel fabric maintains excellent thermal insulation, with a room-temperature thermal conductivity of 0.037 W·m–1·K–1, producing a temperature difference of 27.7 °C on a 100 °C hot plate. Our results establish controlled capillary reconstruction as a scalable structural engineering strategy for manufacturing mechanically robust nanoporous materials through ambient-pressure drying.