High energy-capacity and multiresponsive phase change fibers via in situ polymer composition with expanded carbon nanotube networks.

• Non-destructive electrolysis-induced expansion is used to reconstruct CNT networks. • An in situ composition strategy is proposed to impregnate PEG into CNT network during its expansion. • The in situ strategy results in superhigh PEG loading (96 wt%) and robust PEG confinement inside CNT network. • High thermal and electrical performances are realized for CNT/PEG composite phase change fibers. Phase change fibers with abilities to storage/release thermal energy and response to multiple stimuli are of high interest for wearable thermal management textiles. However, there are long-term challenges for carbon nanotube (CNT) network-directed phase change composites, such as the limited polymer loading, nonuniform composite structure, and weak connectivity between CNTs. Herein, an expansion-based in situ composition strategy is proposed to impregnate polyethylene glycol (PEG) into CNT network, leading to a high and homogeneous PEG loading (96 wt%) and robust PEG confinement inside the expanded CNT network. As the expansion induced CNT separation from aggregation, leading to the full utilization of CNT surfaces, the CNT/PEG composite fibers at the highest PEG loading exhibited superior high latent heat of 195–205 J g−1, and were electrically and thermally conductive. More importantly, owing to the confinement, these fibers showed remarkable cyclic thermal stability, without any liquid leakage. The composite fibers were also embroidered and woven into various fabrics, which showed excellent thermal managing capacity and rapid responses to electrical and optical stimuli. [ABSTRACT FROM AUTHOR]