A Dual Gelation Strategy Under Gravity‐Enhanced Orientation to Construct Super‐Strong and Tough Bacterial Cellulose Phase Change Fiber for Wearable Heat Supply

Abstract The development of wearable heat supply textiles in cold conditions utilizing the photothermal conversion effect is crucial for the advancement of wearable thermal management textiles that do not require any power supply connection or other external energy input. Here, a dual gelation strategy under gravity‐enhanced orientation is proposed to construct super‐strong bacterial cellulose (BC) aerogel fiber using BC as the matrix material and hydroxylated carbon nanotubes (HCNT) as the photothermal conversion material. Under the assistance of orientation property and dual network structure with soft–hard synergy, the silanized BC/HCNT (SBT) aerogel fiber has rich network, tensile strength up to 26.0 MPa, flexibilityand knittability. Thanks to the enhanced network backbone, after the introduction of the phase change material eicosane in SBT aerogel fiber (SBTE), the SBTE fiber achieves high enthalpy of 105 J g −1 , low leakage, storage stabilityand super‐strong and tough mechanical properties of 23.9 MPa and 8.7 MJ m −3 , while maintaining flexibility, knittabilityand hydrophobicity. The textile woven by SBTE fiber also exhibits a long‐lasting heat supply capacity at low temperatures and under real‐world conditions. Therefore, the finely designed SBTE fiber has the potential to be used in solar‐driven wearable heat supply textiles in cold weather.