Flexible\nCapacitive Pressure Sensor\nEnhanced by Tilted Micropillar Arrays

Abstract

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