Microcapsule/Poly(vinyl Alcohol)/MXene Flexible Phase Change Composites: Structure Advantage and Performance Enhancement

To solve the problem of easy leakage caused by unstable distribution of phase change component in flexible phase change composites, the octadecane@polyurethane microcapsule/poly(vinyl alcohol)/MXene (OPM) flexible phase change composites were prepared by mixing and spin coating methods in this work. OPM showed a structure advantage and achieved performance enhancement. The spherical phase change microcapsules were uniformly and tightly distributed in the structure of OPM. On the one hand, this structure effectively prevented leakage of octadecane, thereby maintaining good form stability. On the other hand, this structure effectively avoided direct contact between octadecane and substrate structure, reducing the confinement effect on phase change behavior, making the experimental latent heat (∼123.8 J/g) very close to the theoretical value, thereby achieving enhanced heat storage performance of OPM. Further, the MXene played a crucial role in simultaneously improving flexibility and mechanical performance and enhancing photothermal conversion ability, mainly due to the formation of a cross-linking structure and the strong localized surface plasmon resonance effect of MXene. The mechanical performance (strain: ∼123.00%; stress: ∼15.94 MPa) of OPM depended on the content of microcapsules due to their inherent rigidity. Meanwhile, OPM showed good chemical compatibility, crystallization characteristics, and acceptable thermal stability.