Flexible and Leakage-Proof Sodium Alginate-Based Phase Change Composite Film for Thermal-Comfortable Application of Electronic Devices

Solid–liquid phase change materials (PCMs) with large latent heat can efficiently weaken thermal peaks, thus alleviating the thermal discomfort of human beings caused by electronic devices. However, the leakage during the melting process and the low thermal conductivity severely limit their application in electronic thermal management. In this study, a flexible and leakage-proof sodium alginate-based phase change composite film (PCCF) was first fabricated via a facile and green synthesis method with the assistance of stainless steel meshes, and its synthetic size could be easily regulated via a mold. Multiwall carbon nanotubes (MWCNTs) were used to enhance the thermal conductivity of the PCCF. Through the leakage prevention tests, it can be found that the PCCF-0.7 (the mass fraction of polyethylene glycol (PEG) was 70%) exhibited leakage proof under an external force. The phase change enthalpy of the PCCF-0.7 reached 100.05 J/g, and the enthalpy retention rate reached 76%. The radial thermal conductivity of PCCF-0.7 (contains 8 wt % MWCNTs) was 3.52 W/(m·K), 3810% higher than that of pure PEG. The heat transfer experiment demonstrated that the PCCF could efficiently store thermal energy; the maximum temperature of the analog smartphone could be reduced by 5.3 °C. Hence, the prepared PCCF is suitable for providing thermal comfort to electronic devices, and it is sustainable and eco-friendly.