Dielectric oil coated single-walled carbon nanotube electrodes for stable,large-strain actuation with dielectric elastomers

摘要

Dielectric elastomers have shown remarkably large actuation strain and energy density. A wide range ofnovel applications have been conceptualized, but commercial devices have not materialized due to thehigh rates of failure during high-strain actuation. We report that the use of single-walled carbon nanotube(SWNT) layers with thicknesses in the tens of nanometers as the compliant electrodes in combinationwith dielectric oil can prolong the actuation durability by at least one order of magnitude. Even thoughthe ultrathin SWNT electrodes can undergo localized self-clearing in the event of electrical breakdown,effectively deactivating the fault and enabling self-healing of the device, extended duration actuation atstrains larger than 100% in area cannot be achieved. This is due to corona discharge of the highly porousSWNT electrodes that have sharp tips that amplify the electric field. We show that by applying a dielectricoil coating on the SWNT electrodes, the corona discharging is quenched and continuous actuation at largerthan 150% strain for longer than 1500 min can be achieved. The combination of self-clearable SWNTelectrodes with dielectric oil coating should improve the manufacturing yield and operational reliabilityof dielectric elastomer artificial muscles and push them closer to commercialization.