Assessment of electromechanical performances of PDMS-based flexible capacitive pressure sensors

Porous PDMS based capacitive sensors dedicated to the sensing of force/pressure in biomedical applications have been widely studied this last decade. These sensors are highly popular for their ability to constitute wearable and non- invasive sensing solutions. Nevertheless, the electromechanical behavior of such sensors is strongly non-linear, and therefore their performances are generally difficult to estimate and to compare from one sensor to the other. In this paper, we propose a first order behavioral model allowing the sensitivity and the measurement range to be defined and estimated in a global way. The relevance of the model is validated using experimental data obtained from the electromechanical characterization of a set of porous and non- porous PDMS-based sensors used as test samples. This model also enables the intrinsic limitation of flexible polymer based sensor performances to be determined, knowing the nature of the used polymer and the porosity induced by the fabrication process.