Structurally Modified PDMS-Based Capacitive Pressure Sensor

Abstract

Flexible pressure sensors have gathered a wide interest among researchers for their wide applications in the healthcare, biomedical, automobile, soft-robotics, and aerospace industries. This work presents a PDMS-based capacitive pressure sensor that offers a high sensitivity of > 7 kPa ^-1 for low to medium pressure range (0 to 10 kPa). The introduction of hollow cylindrical cavities in the substrate body and microstructures into the sensor has demonstrated a considerable advantage over the conventional plane structures. The fabrication is performed using the 3D printed replica molding technique. The experimentally obtained sensitivities for sensors with different structural modifications such as the plane unstructured PDMS layer, PDMS layer with hemispherical microstructures of radii 500 µm, hemispherical structures along with hollow cavities are 0.5 kPa ^-1 . 6.77 kPa ^-1 and 7.99 kPa ^-1 respectively. The sensor with hemispherical microstructures along with hollow cavities has shown 11.3 times superior sensitivity performance compared to the other and plane structure. The experimental results are found to be in agreement with the simulation studies. The proposed fabricated sensors with hemispherical microstructures along with hollow cavities can be used for highly sensitive measurements in biomedical applications.