Synergistic integration of porous polymer networks with solid-solid phase change material and surface-modified BN for enhanced thermal conductivity and latent heat storage

Abstract

Conventional phase change materials (PCMs) face two persistent challenges: low thermal conductivity and leakage during phase transitions. Studies have partially addressed these issues using porous carbon supports and core–shell encapsulation. However, these strategies often remain impractical for electronic thermal management applications due to their electrical conductivity or incompatibility with polymer matrices. Therefore, this study aims to develop a fundamentally new strategy that synergistically integrates a reinforced porous polyacrylamide–starch (PAM–S) framework, surface-functionalized agglomerated boron nitride (PA-ABN), and a Bi–Sn–In liquid metal alloy. The starch-modified PAM network enhanced structural integrity and inhibited filler sedimentation, facilitating a uniform filler distribution of the PA-ABN. Surface modification of ABN with polysilazane–silane improved polymer–filler interfacial adhesion and promoted the formation of a continuous, planar, through-plane thermal network, resulting in a higher thermal conductivity (3.34 W/m∙K) than the unmodified ABN composites. Similarly, the well-integrated filler network and reinforced porous framework significantly enhanced mechanical robustness, increasing tensile strength from 2.16 MPa (original PAM) to 14 MPa. The Bi–Sn–In alloy, characterized by high thermal conductivity and a low melting point (62 °C), infiltrated the polymer matrix–filler micropores, further reducing the interfacial thermal resistance. This design led to a composite with a latent heat capacity of 138 J/g and excellent leakage resistance up to 120 °C, maintaining stable thermal performance over 100 cycles and demonstrating superior CPU cooling efficiency compared to conventional thermal interface materials. These findings demonstrate a novel PCM composite architecture that simultaneously achieves leakage control, durability, and high heat-transfer efficiency, making it suitable for advanced thermal management applications.