Flexible and leakage-proof phase change composite for microwave attenuation and thermal management

Miniaturization of high-speed electronics requires multi-functional materials to address electromagnetic interference (EMI) and overheating issues at one time. Phase change material (PCM) could be an ideal solution for thermal management via thermal energy storage to avoid bulky heat sink. Herein, we propose a flexible PCM composite sheets SPP, consisting of the single wall carbon nanotube (SWCNT) and the phase change material-polyethylene glycol (PEG) in a Polydimethylsiloxane (PDMS) matrix. Due to the double-percolation microstructure constructed by SWCNT and PEG, the SPP could exhibit over −20 dB microwave attenuation with great tunability of working frequency throughout the entire 2–18 GHz at a fixed SWCNT filling ratio of only 0.2 vol%. Meanwhile, 70 vol% of PEG can be loaded without compromising the mechanical robustness and great anti-leakage performance, resulting in a latent heat storage density of over 110 J/g. With such superior capability of thermal energy storage, it's demonstrated that the SPP composite sheets could act as cooling patches for electronic components to reduce the working temperature and also stabilize the temperature fluctuations. Based on the above, it is believed that the SPP could shed light on materials solutions of electromagnetic compatibility and thermal mitigation for next-generation ultra-compact electronic systems in a wide frequency range.