Single-Sided Capacitive Pressure Sensor with Tunable Performance Over a Wide Pressure Range

Flexible pressure sensors have a wide range of applications including human body monitoring and robotic control. Recent work has focused on developing pressure sensors that excel at measuring pressure in the ultrasensitive range, often with parallel plate piezocapacitive sensors and a dielectric that relies on microstructures. However, these approaches have a few drawbacks including a limited range and high complexity leading to expensive and time-consuming manufacturing. To mitigate these problems, we demonstrate the fabrication of a low-cost, flexible, interdigitated electrode (IDE) pressure sensor with an overlaid layered elastomer composed of polydimethylsiloxane (PDMS) and Barium Titanate (BaTiO3). The elastomers are manipulated by modifying the mixing ratio, curing temperature, incorporation of BaTiO3, and compressed at two strain rates. Characterization of these elastomers and IDE geometry allows for insights into the behavior and tunability of the layered macrostructure and electrode design. As a result, the leading IDE geometry can be tuned to work in a lower range with a sensitivity of 77.8% per decade between 0 and 10 kPa and 4.5% per decade between 10 and 100 kPa or in a larger range with a sensitivity of 12.9% per decade between 0 and 100 kPa and 3.4% per decade between 100 and 500kPa.