Solution-processed submicron free-standing, conformal, transparent, breathable epidermal electrodes.

Long-term, real-time and comfortable epidermal electronics are of great practical importance for healthcare monitoring and human-machine interaction. However, traditional physiological signals monitoring confined by the specific clinical sites and unreliability of the epidermal electrodes, which leads to great restrictions on its application. Herein, we constructed a solution-processed submicron (down to 230 nm) free-standing breathable sandwich-structured hybrid electrode composed of silver nanowires network with conductive polymer film, which is conformal, water-permeable, and noninvasive to the skin while achieving good signal acquisition ability. The free-standing hybrid electrode is prepared via an in-situ capillary force lift-off process and can be transferred onto complex surfaces. The whole process is a complete solution process that facilitates large-area preparation and application. The light-weight hybrid electrodes exhibit high optical transmittance, high electrical conductivity as well as high gas/ion permeability. When attached the hybrid electrodes onto the skin, the imperceptible films show high conformality with low electrical impedance, thus exhibits significantly improved electrocardiology and electromyogram signals monitoring performance compared to that of the commercial gel electrodes.