Highly Stretchable Electronic-Skin Sensors with Porous Microstructure for Efficient Multimodal Sensing with Wearable Comfort

Wearable electronic skins have aroused extensive interest in health detection, human-computer interaction, and robotics. However, it remains a great challenge to realize the multifunctional electronic skin with a wide detection range, high sensitivity, multi-stimulus response, and wearable comfort on a single device. Here, a flexible porous thermoplastic polyurethane (TPU)/carbon black (CB) multimodal sensor that perceives multiple stimuli of pressure, strain, and humidity is prepared by the water vapor-induced phase separation method. The as-prepared device exhibits a wide pressure detection range (up to 49 kPa), excellent sensitivity (0.21 kPa(-1)), fast response (150 ms), and recovery time (120 ms). Furthermore, as a strain sensor, it is not only highly stretchable (730%), but also can operate over a strain range of 0-240% with a sensitivity of up to 1485.2 and excellent durability. Moreover, the designed sensor can detect humidity changes from 35% to 90% and has a fast response time (1.2 s), while enabling non-contact sensing of a fingertip. Importantly, the porous TPU/CB film presents excellent breathability, enabling it to achieve a high level of comfort. Therefore, the perfect integration of these features ensures the potential applications of porous TPU/CB sensors in human activity detection, exhale monitoring, and breathable wearable devices.