Integrating boron nitride and hydroxylated graphene in phase-change films for flexible electronics cooling

Wu, X. and Liu, M. and Pan, Y. and Liu, Y. and Lv, C. and Chang, Z. and Du, Y. (2025) Integrating boron nitride and hydroxylated graphene in phase-change films for flexible electronics cooling. Carbon, 244: 120696. ISSN 0008-6223

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Abstract

With the rapid development of flexible electronic technologies, there is a growing demand for high-performance, flexible thermal interface materials (TIMs) capable of efficiently dissipating heat while conforming to complex device geometries. Phase-change films (PCFs), owing to their inherent latent heat storage capabilities and favorable processability, have emerged as promising candidates for such applications. However, integrating high thermal conductivity with effective phase-change functionality and mechanical flexibility remains a major technical challenge. In this study, a series of novel phase-change films (PCFs) were successfully fabricated using a solvent evaporation method. Polylactic acid (PLA) served as the support material, polyethylene glycol (PEG) acted as the phase-change medium, and highly thermally conductive particles including boron nitride (BN) and hydroxylated graphene (OH-GN) were employed as thermal conductive fillers to establish efficient heat conduction pathways. The experimental results indicate that the composite PCFs exhibit excellent thermal reliability and functional performance in diverse conditions. The newly fabricated PCFs demonstrate strong leakage resistance at 80 °C, high phase-change enthalpy (>97.95 J/g), and enhanced thermal stability, while maintaining good mechanical flexibility. The thermal conductivity of the PCFs was significantly improved with the addition of conductive fillers. Specifically, the incorporation of 20 wt% BN increased the thermal conductivity to 0.40 W/(m·K), marking a 222.22 % enhancement over the baseline PLA/PEG film. Notably, the composite PCFs containing 9 wt% OH-GN achieved the highest thermal conductivity of 0.86 W/(m·K), corresponding to a 477.78 % increase. Furthermore, OH-GN significantly enhanced the photothermal conversion performance of the PCFs due to its strong light absorption. The PCF-11 (with 9 wt% OH-GN) exhibited a photothermal conversion efficiency of 91.7 %. Under a controlled environment at 45 °C, the temperature of a pure PLA film rapidly rose to 44 °C, whereas the PCF-11 exhibited a slower and more stable temperature increase, indicating effective thermal buffering. These results confirm the substantial potential of the composite PCFs in next-generation thermal management applications for flexible and wearable electronic devices.