Characterization of slide ring materials for dielectric elastomer actuators

This paper investigates the characteristics of sliding ring materials (SRMs), which are promising elastomeric materials for dielectric elastomer actuators (DEAs). Two different types of SRMs with Young's modulus of 0.8 MPa and 3.3 MPa, respectively, are prepared, and their material and mechanical properties and electro-mechanical performances at electric fields of up to 30 V mu m(-1) are characterized. For comparison, the same tests are also performed on several commercially available elastomers: Elastosil 2030, Ecoflex 00-30, CF19-2186, and VHB 4905. The results reveal that SRMs demonstrate negligible Mullins effect and hysteresis, while their dielectric strength (62.4-112.4 V mu m(-1)) and viscoelasticity (tan delta 0.07-0.24 at 10 Hz) are comparable or even superior to those of other elastomers. In addition, elongation at break is found to be 163.8%-172.1%. SRMs exhibit excellent electro-mechanical performance; for instance, one of the two types has an actuation force 293.2 mN at 24.9 V mu m(-1) and a strain of 5.2% at 22.3 V mu m(-1). These values are the largest or larger than most of the tested elastomers. The high performance of SRMs results from their dielectric constant, which ranges from 10.3 to 13.4, leading to an electro-mechanical sensitivity of up to 15.3 MPa-1. These results illustrate SRMs as attractive material options for DEAs.