Morphologically intelligent dielectric elastomer sensors based on micro-structured electrodes as resistive strain elements

Abstract

Dielectric elastomer sensors (DES) are compliant systems that, allow the detection of geometric changes caused by external forces. However, a simple DES provides only the amplitude of a deformation. In order to fully describe a tensile force vector, it is necessary to characterize it by its length, direction, and origin. Therefore, there are many approaches to improve the information that can be obtained from the sensor, such as arranging DES patterns or modifying the impact of the applied mechanical force by using external components. To improve and parallelize the information provided by the mechanical deformation of the system, we aim to combine the operation principle of structured resistive strain sensors with the capacitive properties of DES. By structuring the electrodes with different patterns and combining two dissimilar electrodes in one setup, it is possible to detect the length and direction of a force vector with one sensing element. To study the patterning and its effect on resistive and capacitive signals, we use an aerosol jet printing technique that allows selective deposition of a conductive ink. The printed lines show a higher resistance increase when forced perpendicular to the pattern and vice versa, which allows to distinguish the direction and the type of applied force. In this study, the influence of printing parameters and signal interpretation for different forces are investigated. The results show that the combination of resistive and capacitive signals allows discrimination between different motions.