Biomimetic integration of tough polymer elastomer with conductive hydrogel for highly stretchable, flexible electronic

Flexible electronics is booming and attracts considerable interest in monitoring physiological activities and health conditions. The development of human-friend flexible electronics with both excellent human movement monitoring and flexible electrode functions at a wide working range remains highly challenging. Herein, we report a biomimetic double-layered multifunctional flexible electronic device composed of a stretchable, tough elastomer covalently coupled with a conductive, double-network hydrogel for monitoring physiological motions. The introduction of optimal physical crosslinking including hydrogen bond and metal coordination in the covalently cross-linked polyurethane elastomer effectively provides favorable flexibility and stretchability. The elastomer-hydrogel integration (EHI) shows ultra-fast responsiveness (10 ms) and resilience (246 ms) as a skin sensor and could effectively detect diverse muscle and joint movements in a highly sensitive and signal waveform-interpreting manner. Further, such a polymer integration with skin shape-adaptive hydrogel and low contact impedance enables real-time high-quality detection of electrocardiogram (ECG) by serving as flexible electrode compared to commercial Ag/AgCl electrodes, and was successfully applied to measure electrooculogram (EOG) and electromyogram (EMG). EHI-based electrodes were feasible and effective for electroencephalogram (EEG) signal detection in brain-computer interfaces (BCI) system. Altogether, this biomimetic EHI electronic device provides an advanced platform for the design of next-generation flexible healthcare diagnostic monitors and soft robots.