A flexible phase change composite encapsulated in cellulose nanofiber/ polyacrylamide layered porous structure for thermal energy storage and management

Phase change materials (PCMs) exhibit significant application potential as thermal management materials across various sectors, especially composite PCMs with mechanical flexibility and high latent heat. Despite recent advances in PCMs encapsulation technology, their applications are often severely limited by insufficient mechanical properties and complex manufacturing processes. Herein, a layered engineering strategy of a three-dimensional network structure was reported, achieving PEG encapsulation and a mechanically flexible support structure. Benefiting from the synergy of rigid cellulose nanofibers and flexible polyacrylamide hydrogel, the prepared phase change composites achieve a noteworthy level of flexibility and tensile strength (4.9 MPa), along with significantly high latent heat (138.5 J/g) and thermal cycle stability. These bendable and foldable flexible composites with phase transition properties are suitable for the thermal management of complex equipment particularly as a potential candidate material for environmental temperature regulation and thermal protection. Overall, this work proposes a novel strategy to combine hydrogel and biomass materials to prepare support frameworks for PCMs encapsulation, which will foster potential advances in flexible phase change composites.