Design of flexible resistance sensor based on mesh convex microstructure

To solve the problems of large volume and poor flexibility of the traditional pressure sensor prepared by rigid materials, a flexible pressure resistance sensor with mesh convex platform microstructure is prepared by using PDMS as a substrate and graphene as a conductive functional layer. The preparation process of the conductive layer and the substrate of the sensor are optimized. The effect of the concentration of graphene and thinckness of PDMS on the sensor’s sensitivity are investigated. The experimental results show that the addition of polyurethane to graphene and the hydrophilic treatment of the PDMS can improve the stability of the sensor. Excessive graphene blocks the microstructural gaps resulting in reduce sensitivity. The thicker the PDMS, the smaller the microstructural deformation, resulting in lower sensitivity. Based on the theoretical basis of elastic mechanics, the calculated results consistent with the experimental results. Finally, the performance of PDMS microstructure sensor with thickness of 0.2mm is tested. The sensor has a high linear sensitivity (0.152kPa-1) and a wide linear dynamic response range (0-4kPa), along with a fast response time of 83ms. The sensor is fixed to the finger for bending test and shows that the sensor is able to detect human physiological activity.