Skin mimicking-sweating evaporation polyimide cooling film for electronic devices

In hot environments, the human body shows an efficient capability to maintain a stable temperature by benefiting from sweating behavior. Inspired by this skin perspiration strategy, in this study, we demonstrated an innovative polyimide foam (PIF)-based mimetic skin with excellent cooling capability by integrating a silver coating and reusable hydrogel for the first time. Because of the hybrid thermal dissipating system, the successive silver coating quickly transferred heat to the inside of the polyacrylamide hydrogel. Meanwhile, the hydrogel absorbed a large amount of heat due to its large enthalpy and effectively dissipated heat to the environment through the evaporation of moisture, similar to the sweating of skin. Thus, the temperature of the skin-like film was reduced by 25.4°C compared with pure PIF under a high-power laser heating source. Identical and remarkable cooling effects were also obtained in mobile phone and battery applications, far better than commercially available thermally conductive polyimide (PI). This outstanding performance paves a new way for the thermal management application of PI in wearable electronics, microprocessors, and flexible electronics.