Complaint liquid metal electrodes for dielectric elastomer actuators
This work presents a liquid-phase metal electrode to be used with poly(dimethylsiloxane) (PDMS) for a dielectric
elastomer actuator (DEA). DEAs are favorable for soft-matter applications where high efficiency and response times are
desirable. A consistent challenge faced during the fabrication of these devices is the selection and deposition of electrode
material. While numerous designs have been demonstrated with a variety of conductive elastomers and greases, these
materials have significant and often intrinsic shortcomings, e.g. low conductivity, hysteresis, incapability of large
deformations, and complex fabrication requirements. The liquid metal alloy eutectic Gallium-Indium (EGaIn) is a
promising alternative to existing compliant electrodes, having both high conductivity and complete soft-matter
functionality. The liquid electrode shares almost the same electrical conductivity as conventional metal wiring and
provides no mechanical resistance to bending or stretching of the DEA. This research establishes a straightforward and
effective method for quickly depositing EGaIn electrodes, which can be adapted for batch fabrication, and demonstrates
the successful actuation of sample curved cantilever elastomer actuators using these electrodes. As with the vast majority
of electrostatically actuated elastomer devices, the voltage requirements for these curved DEAs are still quite significant,
though modifications to the fabrication process show some improved electrical properties. The ease and speed with
which this method can be implemented suggests that the development of a more electronically efficient device is realistic
and worthwhile.