Long lifetime, fault-tolerant freestanding actuators based on a silicone dielectric elastomer and self-clearing carbon nanotube compliant electrodes

Abstract

We explore the effect of pre-stretch and application of mechanical loads on a soft polydimethylsiloxane (PDMS) elastomer to obtain high linear strain freestanding dielectric elastomer actuators. It is shown that when the mechanical loads are properly applied, large linear actuation strains of 120% and work density of 0.5 J cm⁻³ can be obtained due to a transition from pure-biaxial to pure-uniaxial actuation conditions. Furthermore, we demonstrate that when coupled with single wall carbon nanotube (SWNT) compliant electrodes, fault-tolerance is introduced via self-clearing leading to significantly improved operational reliability. Cycling actuation tests reveal that even after more than 30 self-cleared electrical breakdown events the actuators maintain a high level of performance. Driven at moderate electric fields, the actuators display relatively high linear actuation strain (25%) without degradation of the electromechanical performance even after 85 000 cycles.