High‐Performance Phase Change Films Prepared by a Strategy for Thermal Management at Interfaces and Environmental Camouflage

With the development of electronic equipment and the advancement of environmental camouflage technology, higher requirements are placed on the flexibility, thermal conductivity, and heat storage capacity of phase change films. This work fabricated a high-performance dual-encapsulation composite phase change film through the employment of Pickering emulsion polymerization and sol-gel techniques, incorporating n-octadecane (n-OD), liquid metal gallium (Ga), and poly(p-phenylene benzobisoxazole) (PBO). Phase change microcapsules (PM) serve to prevent leakage during phase changes, maintain high levels of enthalpy, and enhance the dispersion of n-OD in matrices, as well as improve adhesion at interfaces. It is possible to achieve excellent thermal conductivity with only a small amount of modified Ga (MGa) by chitosan quaternary ammonium salt in the confined network since the material has a smaller size and a more uniform distribution. Owing to its distinctive structural design and modification strategy, the composite phase change film (MGa/PM/PBO) manifests outstanding mechanical properties (featuring a tensile strength of 7.0 MPa), remarkable thermal conductivity (9.4752 W m^-1 K^-1) in-plane), and excellent heat storage capacity (100.9 J g^-1). It harbors significant potential for application in the thermal management of electronic devices and in environmental camouflage.