Stretchable Tactile Sensor with High Sensitivity and Dynamic Stability Based on Vertically Aligned Urchin-shaped Nanoparticles

Abstract Stretchable tactile sensor (STS) is promising for wearable electrical devices, human-machine interfaces, and electronic skin. However, developing a piezoresistive composite STS with high-pressure sensitivity and dynamic stability remains challenging because stretching deformation destroys the original dispersed state of conductive fillers. This interference of stretching strain on the pressure sensing greatly reduces device performance. Here, we realize an STS based on a piezoresistive composite with different elastic moduli in its functional regions. The composite contains high elastic modulus regions (59.1 MPa) of vertically aligned columns of urchin-shaped nanoparticles, and low elastic modulus regions (2.4 MPa) of pure matrix. The sensor exhibits high-pressure sensitivity (12.05 kPa-1) due to the increased conductive contact area between urchin-shaped nanoparticles in the high elastic modulus region. While stretching to 400% strain, the sensor exhibits excellent dynamic stability via strain accommodation in the low elastic modulus region. Our method of elastic modulus regulation is easy-operative and universal to separate sensing from multiple stimulus. In addition, the sensor has a low hysteresis coefficient (5.25%), a good detection limit (22 mg), a low response/recovery time (