Flexible Drucksensoren aus Dielektrischen Elastomeren

Dielectric elastomer sensors (DES) offer extended possibilities for the detection of strains and forces under tensile load, using a capacitive measuring principle. However, for the measurement of pressure loads, they are very insensitive due to the small deformations. To close this gap, novel sensor mats have been developed, which react very sensitively to pressure loads. The basic design of the sensor mats consists of two elastomer profiles, between which an elastomer film is located. Under compression of the sensor mat, the profiles penetrate into each other and stretch the elastomer film strongly. This effect causes strong changes of the electrical capacitance. For the design of the sensor mats, multiple possibilities of variation are available, with which the characteristics of the dependence of capacitance on load can be influenced and tuned. This includes geometrical parameters such as the shape of the profiles and the location of the electrodes as well as materials parameters like the hardness of the profiles and the elastomer film. These correlations are outlined in the paper by means of some examples. The new sensor mats can be beneficially exploited in all scenarios, in which pressure measurements on extended compliant surfaces such as seats, beds or shoes are required