Highly stretchable pressure sensors with wrinkled fibrous geometry for selective pressure sensing with minimal lateral strain-induced interference

Emerging electronic skin (e-skin) poses urgent needs for high-performance pressure sensors. However, the state-of-the-art pressure sensing electronics require further advances to simultaneously satisfy the multiple parameters including high sensitivity, wide sensing range, good stretchability and selectivity. Especially, selective pressure detection without interference from lateral strain is highly demanded for a pressure sensor to mimic skin touch sensation. Here, high-performance pressure sensors were fabricated through developing periodic wrinkles and fibrous network geometries into the piezoresistive layer. The obtained wrinkled conductive fibrous mat (wrinkled-CFM) sensor showed high pressure sensitivity (186.5 kPa−1) accompanied by an ultra-wide working window (0–550 kPa) and good mechanical stability. To tackle the intrinsic instability of MXene nanosheets, CFM was treated with fluoroalkylsilane to achieve a hydrophobic surface, enabling long-term reliable sensing with minimal conductance variation (<9%). In addition, the wrinkled-CFM was also integrated with a stretchable interdigited electrode based on elastomer fibrous mat to achieve a highly stretchable (>100%), pressure-sensitive and lateral strain insensitive (with a low gauge factor of ~0.25) sensor that can be stretched for thousands of cycles without sensing function degradation, demonstrating great potential for the future e-skin application.