Carbon nanotube bundles assembled flexible hierarchical framework based phase change material composites for thermal energy harvesting and thermotherapy

Conventional single thermal nature of phase change materials (PCMs) seriously obstructs their frontier applications. Herein, we designed advanced carbon nanotube (CNT) bundles assembled flexible hierarchical framework based phase change material composites for high-performance thermotherapy of allergic rhinitis. Hierarchically interconnected 3D freestanding flexible CNT sponge was constructed via a facile organic solvent-free route using table salt as a sacrificial template. The resulting hierarchical CNT sponge serves as an ideal compatible supporting host and polyethylene glycol (PEG) serves as an excellent thermal energy guest. Subsequently, we designed advanced portable integrated functional mask consisting of outer air purification layer and inner thermal regulation layer for the thermotherapy of allergic rhinitis, in which pristine CNT sponge serves as an excellent particulate matter capturer and PEG-infiltrated CNT sponge serves as a superior thermal regulator. Strikingly, our uniquely constructed flexible CNT sponge-involved composite PCMs assisted by polyvinylidene fluoride (PVDF) harvest high-performance thermotherapy (~33 ​min of the plateau at ~43.5 ​°C). The corresponding medical results (HE staining and Wrights staining) further indicate that our designed thermotherapy mask can significantly reduce the inflammatory injury of nasal mucosa. Additionally, pristine hierarchical CNT sponge guarantees the inhaled air quality and enhances the thermotherapy effect. This synthetic strategy can be scaled up for large-scale production. This novel functional host-guest strategy creates an innovative platform for developing advanced multifunctional PCMs with multiple fascinating peculiarities and desired functional properties and teaches an old dog new tricks.