Inspired by heat exchanger fins: Enhanced thermal properties of flexible phase change composites with copper reticulated nanofin-modified carbon fiber mat reinforcement

Advances in 3D phase change composites (PCCs) are progressively transforming thermal energy storage and management through enhanced thermal performance and photothermal conversion. However, the arena lacks versatile materials tailored for a diverse array of geometries. This study introduces an innovative, shape-adaptive paraffin wax (PW) based PCC with shape memory attributes which are activated by solar and thermal energies, termed CuRNFFM@PW. Inspired by heat exchanger fins, the flexible PCC is synthesized by reinforcing a carbon fiber mat (CFM) with dense, uniform copper nano-network fins, which exhibit a lattice-like structure on the carbon fibers. The CuRNFFM@PW exhibits a substantial upsurge in thermal conductivity , reaching 1.79 W m -1 K -1 —a 746 % increase over pure PW and a 504 % improvement compared to CMF@PW. Furthermore, the composite boasts near-perfect thermal shape recovery (nearly 100 %), a good thermal storage enthalpy of 171.1 J g -1 , and robust photothermal efficiency. Collectively, these attributes herald the CuRNFFM@PW as a promising candidate in solar thermal energy storage and in the thermal regulation of uniquely shaped electronic devices.