Friction for flexible pressure sensors and arrays on polymers

The rapid development of internet technology and artificial intelligence drives the demand for flexible sensors. Compared with vacuum technology and solution method, the fabrication of flexible sensors by pencil writing directly has advantages such as low cost, simple operation, low temperature, and no pollution. However, they are based on paper and rely on rigid fibers on the surface of it. The polymer is comfortable, portable and has excellent tensile properties, making it more suitable than paper as flexible substrates for wearable devices. In this paper, flexible pressure sensors and arrays are prepared by friction on polymers (Eco-flex、PDMS and bionic skin). The sensitivity of the prepared pressure sensor was 0.78 kPa−1 in the range of 20 kPa, and the response time was 400 ms, while the pressure detection ranged up to 160 kPa. Finally, it can be reused for 1000 cycles. As a wearable device, it can be applied to object grasping, muscle movement and respiratory monitoring. Furthermore, by combining the friction process with the transfer printing process, the stretchable flexible pressure sensor can be prepared on 3D cylindrical and curved hemispherical surfaces. Moreover, patterned sensors can also be prepared. It should be noted that the sensor can be cleaned after being discarded and has no pollution to the environment due to the mild type of materials, which is of certain significance for the development of flexible sensors towards green and low-cost development trends.