Novel dielectric elastomer sensors for the measurement of elevated pressure loads

A novel design for dielectric elastomer pressure sensors based on a capacitive measurement principle is introduced. Compared with easily compressible and highly sensitive dielectric elastomer sensors containing internal voids, the new sensors are compact and suitable for an elevated pressure range up to about 2 MPa. In these sensors, a dielectric elastomer film with several dielectric and electrode layers is covered on both surfaces by plates, which exhibit a pattern of openings. When the sensor film is compressed, the elastomer material can expand into these openings, which reduces the film thickness and increases the capacitance. The dielectric elastomer film consists of a soft silicone with carbon black particles in the electrode layers. With this design, the sensitivity of the pressure sensors in terms of the capacitance increase is enhanced in comparison with reference sensors without openings in the plates and the disturbing hysteresis of the capacitance vs. pressure curves is reduced. With FEM Multiphysics simulations, the capacitance enhancement upon pressure increase and the sensor deformation were calculated and compared with experimental data. In a systematic study, different parameters of the sensor design were varied, in order to evaluate their influence on the sensor performance. The results of this study are presented in the paper.