Highly sensitive and wide linearity flexible pressure sensor with randomly distributed columnar arrays

Flexible pressure sensors with high sensitivity and a wide linear pressure response range have great potential in human health monitoring and robotics. Nevertheless, the performance and control of flexile sensors with specialized microstructures need to be enhanced. This work constructed a normal randomly distributed columnar array with a flexible interdigital electrode as the active layer. The array was prepared by aerosol printing instead of the traditional inversion method. This enabled effective control of the columnar array structure. Sandpaper inversion was used to fabricate the contact layer of a film consisting of Ecoflex00-30 and multi-walled carbon nanotubes, forming a bilayer contact resistive structure. The interlocking flexible pressure sensor was packaged and simplified into two layers. Experimental results show that the designed flexible pressure sensor has a high sensitivity of 38.25 kPa(-1), fast response time of 43 ms, and relaxation time of 49 ms. Meanwhile, the stability was excellent over a wide linear range from 0 to 128 kPa. The sensor also performs satisfactorily in monitoring physiological health signals such as human pulse and sound vibration.