Flexible Capacitive Pressure Sensor Enhanced by Tilted Micropillar Arrays

Abstract

Sensitivity of the sensor is of great importance in practical applications of wearable electronics or smart robotics. In the present study, a capacitive sensor enhanced by a tilted micropillar array-structured dielectric layer is developed. Because the tilted micropillars undergo bending deformation rather than compression deformation, the distance between the electrodes is easier to change, even discarding the contribution of the air gap at the interface of the structured dielectric layer and the electrode, thus resulting in high pressure sensitivity (0.42 kPa^-1) and very small detection limit (1 Pa). In addition, eliminating the presence of uncertain air gap, the dielectric layer is strongly bonded with the electrode, which makes the structure robust and endows the sensor with high stability and reliable capacitance response. These characteristics allow the device to remain in normal use without the need for repair or replacement despite mechanical damage. Moreover, the proposed sensor can be tailored to any size and shape, which is further demonstrated in wearable application. This work provides a new strategy for sensors that are required to be sensitive and reliable in actual applications.