Detection Range Enhancement of Stretchable Ultrasensitive Crack‐Based Strain Sensor with Ordered Ag Nanowire Micromeshes for Human Epidermis Monitoring

The muscle contractions in human epidermis carry abundant information for medical diagnostics and health monitoring. Traditional crack‐based strain sensors possess high mechanosensitivity, but have limited stretchability for human epidermis monitoring. Herein, by coupling the complementary effects of two parallel connected cracked gold (Au) film electrodes and an engineered ordered layer of Ag nanowire micromeshes (Ag NMs), a strain sensor with enhanced extensibility as well as high sensitivity is provided. The Au and Ag NMs sensory layers separated by poly(dimethylsiloxane) (PDMS) matrix can be equal to two resistors in parallel, and the Ag NMs would provide stable alternative current pathways to ensure the efficient electronic transport even at high strains when Au layer totally ruptures. The resultant sensor possesses wide detection range of up to ≈22%, great sensitivity (a gauge factor of 2658.9 within 16% strain, and 11026.7 with strain of 16–20%), quick response and relaxation time (≈180 ms/≈200 ms), and excellent durability (≈1000 stretching–releasing cycles). Various human epidermal signals can be recognized by the sensor, which demonstrate great potential applications in wearable healthcare monitors, electronic skins, and intelligent devices.