Effects of Thinner Compliant Electrodes on Self-Clearability of Dielectric Elastomer Actuators

Abstract

A metalized plastic capacitor stands a higher chance to clear faults when embodied with thinner electrodes. However, it is not clear whether the same thickness effect applies to carbon-based compliant electrodes in clearing the defects in dielectric elastomer actuators (DEA). This experimental study showed that charcoal-powder compliant electrodes act like fuses and current limiters to successfully clear the defects of an acrylic dielectric elastomer actuator, provided a very thin electrode coating. For example, DEAs with 3 μm thick (average) charcoal-powder electrodes fast cleared faults and sustained high breakdown strength (300 to 400 MV/m), but the ones with thicker charcoal-powder electrodes (30 μm thick on average) succumbed to persisting breakdowns in a weaker electric field (200 to 300 MV/m). Thermo-gravitational analysis and differential scanning calorimetry showed that dielectric elastomer (3M VHB F9473PC) started to ignite at 350 ∘C, and charcoal powders (Mungyo charcoal pastel MP-12CP) started burning above 450 ∘C. This confirmed that flash ignition and its damping of charcoal powder is possible only with a very thin electrode coating relative to acrylic elastomer substrate thickness. Too thick of a charcoal-powder coating could lead to the spread of burning beyond the initial flash point, and incomplete burning that punctures the dielectric layer but shorts across opposite electrodes. With this insight, one can design self-clearable electrodes to improve the dielectric strength of dielectric elastomer actuators.

Transformation from Helmholtz to Membrane Resonance by Electro‐Adhesive Zip of a Double‐Layer Micro‐Slit Acoustic Absorber

“…Fault Tolerance Test: To make a fault-tolerant electro-adhesive membrane, the electrode material must be self-clearable to avoid puncturing of the air-tight dielectric laminate. [63][64][65] The cured AgNW-filled PEDOT: PSS line was measured with a 0.4Ωmm resistivity. To test the fault tolerance, the samples of electro-adhesive membrane was activated by a ramp of the cyclic voltage pulse as shown in Figure S1 (Supporting Information).…”

Soft End Effector Using Spring Roll Dielectric Elastomer Actuators

“…The forces and voltage can now be determined given a suitable energy function, W(λ 1 , λ 2 , D), for the incompressible DE [9]. Setting D = εE, where ε is the relative permittivity of the membrane, and integrating Equation (7) with respect to D gives…”

“…Another benefit to this material is that it can be pre-stretched, which offers substantial actuation performance, including higher efficiency and dielectric breakdown voltages, and reduces the probability of pull-in instability [6]. The thickness of the compliant electrode used also affects the performance of the actuator, with thinner electrodes generally being favoured over thicker ones provided that the electrode maintains its conductivity for the expected strains [7]. When a voltage is applied to the DEA, it becomes part of the circuit, i.e., a compliant capacitor.…”

Characterizations and Inkjet Printing of Carbon Black Electrodes for Dielectric Elastomer Actuators

“…Inks were comprehensively characterized and further used to print DEA electrodes on VHB. The innovation of this work is highlighted by the capabilities of the developed ink (Ink-TGME/CLB), which achieves stable drop formation with a small nozzle (17 × 17 μm), high printing resolution (droplet size/line width: ∼25 μm), and the largest area strain (80.63%) when compared with DEAs with CB powder electrodes in literature. , This disclosed ink recipe is well suited for fabricating DEA electrodes and is also helpful for the miniaturization of soft and stretchable electronics.…”