Highly stretchable liquid metal/nanofiber films for electromagnetic interference shielding, self-cleaning and temperature-visualizing

Abstract

Developing stretchable electromagnetic interference (EMI) shielding materials is highly desirable for integrated flexible electronic devices, because they often suffer from the decrease of EMI shielding effectiveness (SE) under large tensile deformation. Combining elastic polymers and liquid metals (LM) together may provide a promising solution. However, it is still a great challenge to understand how to avoid the leakage of LM under tensile deformation. Herein, layer-by-layer thermoplastic polyurethane/liquid metal (TPU–LM) composite films with a nanofiber–LM interlocked structure are prepared. The porous TPU nanofibers provide a supporting skeleton with high mechanical properties to encapsulate the LM to avoid its leakage, and the LM layers can therefore maintain a continuous conductive network when it is stretched significantly. As a result, the TPU–LM composite film not only exhibits high EMI SE and anti-leakage performance under large tensile deformation, but also presents excellent chemical resistance, high/low-temperature resistance (−196 to 100 °C), self-cleaning and temperature-visualizing performances, indicating potential applications in flexible wearable electronic devices with large deformation. In short, the composite films with a nanofiber–LM interlocked structure not only provide a promising solution to avoid the leakage of LM in practical applications, but can also be used in self-cleaning and temperature-visualizing multifunctional applications.