Effects of Solvents on the Material Properties of Screen-Printed Electrodes and a Polydimethylsiloxane Dielectric for Dielectric Elastomer Transducers

Abstract

Dielectric elastomer transducers (DETs), namely, highly stretchable dielectric membranes sandwiched between two compliant electrodes, allow to develop sensors, actuators, and generator systems. DET performance is strongly influenced by the material properties of dielectric and electrodes, as well as the type of manufacturing process. For instance, when manufacturing the electrodes via screen-printing, significant amounts of solvents are needed to adjust the printing materials’ viscosity, but they potentially alter DET properties. The investigation of this effect, however, is largely unexplored. Addressing this issue, this article investigates the influence of various solvents on a DET consisting of a polydimethylsiloxane (PDMS) membrane with PDMS/carbon black electrodes. Physical and chemical interactions between dielectric and solvents are characterized by infrared-spectroscopy (IR), optical investigations, and light microscopy. Different solvents used for screen-printing are analyzed in terms of their effects on the electrode electrical resistance, screen-print image, and breakdown strength. Even though the solvent strongly affects the electrodes’ electrical resistance (ranging from ≈22 kΩ to >MΩ), it does not modify the breakdown strength of the pure dielectric (113 V μm−1). In the IR, no chemical aging is found. The obtained results provide systematic guidelines for the choice of solvents in DET electrode manufacturing.