Highly stretchable silicone elastomer applied in soft actuators

In this work, a highly stretchable silicone elastomer is incorporated into dielectric elastomer actuators (DEAs) in order to decrease operation voltages by applying high prestretches. Results show that the fabricated DEAs (5-mm-diameter circle active region) can be actuated to a lateral strain of 30% at 4.3 kV for a 122 μm-thick prestretched film, and to a lateral strain of 2.5% at only 250 V for a 6.9 μm-thick prestretched film. Due to the significant viscous component of the silicone elastomer, the DEAs respond more slowly (2-14 s to reach 90% of full strain) and show greater strain changes over time compared to conventional silicone-based DEAs. While this inherent viscosity is not universally favorable, it can be advantageous in applications where actuator damping is desirable. The studied DEAs’ mean lifetimes under DC actuation range significantly—from 0.9 h to more than 123.0 h—depending mainly on initial electrical fields (17.8-36.3 V/μm). For instance, DEAs with a 150 μm initial thickness and a prestretch ratio of 3 show 1.4-2.6% lateral strains for the mean lifetime (123.0 h) at only 300 V. Given the strains achieved at low voltage, such DEAs show promise for applications that do not require fast response speeds.