Ultrathin, Stretchable, and Breathable Epidermal Electronics Based on a Facile Bubble Blowing Method

Abstract Ultrathin, stretchable, and breathable epidermal electronics are of great significance for wearable and implantable health‐monitoring devices owing to their unique skin‐conformable and skin‐friendly capabilities. However, the poor gas permeability of planar substrates with thicknesses of microns to millimeters, in conjunction with the existing tedious and expensive fabrication methods, has severely limited the realization of high‐performance epidermal electronic devices. Here, a novel bubble blowing method is proposed to fabricate a 150‐nm‐thick, stretchable (62%), breathable (water vapor transmission rate = 580.18 g m −2 d −1 ), and transparent (83% at 550 nm) epidermal electrode based on a freestanding thermoplastic elastomer (TPE) nanomembrane. The ultrathin epidermal electrode can be conformably attached to human skin for high‐quality electromyogram signal recording. Moreover, the device is also demonstrated as a bionic electronic eardrum (vibration sensor) to detect sound with ultrahigh sensitivity (969.3 kPa −1 ) and high signal‐to‐noise ratios (51 dB at maximum) over the wide frequency range of 0–22 000 Hz. The proposed epidermal electronic device provides a novel avenue for future conformal wearable medical devices, human–computer interfaces, and implantable acoustic equipment.