Dielectric elastomer materials for large-strain actuation and energy harvesting: a comparison between styrenic rubber, natural rubber and acrylic elastomer

This paper compares the performance of commercially available membranes made of styrenic rubber, natural rubber and acrylic elastomer for dielectric elastomer transducers (DETs) operating in the large strain regime. Following a detailed description of the adopted experimental set-up and procedures, the results of a comprehensive electro-mechanical characterization of the three materials are reported to highlight the following dependencies: dielectric strength versus stretch, electrical conductivity versus electric field, dielectric constant versus stretch, stress versus stretch and strain rate. This includes the fitting of the experimental data with constitutive equations which provide material property values that can be used for model-based analysis, design and control of dielectric elastomer actuators and generators operating at large levels of strain amplitudes (like, for instance, transducers featuring actuation and generator strains over 50%) or in the presence of large pre-strains (over 50%). Performance metrics relying on the identified constitutive parameters are introduced in order to discuss the specific pros and cons of the considered elastomers for the development of practical DETs.