PDMS/graphite stretchable electrodes for dielectric elastomer actuators

Abstract

Dielectric elastomer actuators (DEAs) consist of an elastomer sandwiched between two electrodes, and they undergo a large in-plane expansion upon the application of an electric field. They therefore require compliant electrodes that can stretch tens of percent. The most commonly used electrode material is carbon grease, which smears easily and is difficult to pattern. This paper outlines the fabrication and performance of a novel polydimethylsiloxane (PDMS) composite having a 15 wt% loading of exfoliated graphite (EG). This new material has a Young's modulus of only 0.9 MPa and a conductivity of 0.15 S/cm. Unlike other composite electrode materials, the Young's modulus of the PDMS/EG increases only slightly, by a factor of two, upon addition of the EG. Furthermore, the PDMS/EG composite is patternable and will not rub off. DEAs were fabricated with 20:1 PDMS as the elastomer using this new electrode material. The actuation strains were equal to those of 10:1 PDMS DEAs with carbon grease electrodes under the same electric field. Elastomer/EG composites may also find applications in areas such as flexible electronics, robotics, strain gauges, and sensors.

High-cycle electromechanical aging of dielectric elastomer actuators with carbon-based electrodes

“…The most widely used electrodes within the DEA community [18][19][20][21][22] are loose carbon powder, carbon grease and conductive rubber, for cost, ease of patterning, low mechanical stiffening, and lifetime reasons. A very wide range of compliant electrodes have been used for DEAs, as reviewed in [20] and [22].…”

Nanoparticle Filler Content and Shape in Polymer Nanocomposites

“…and Offeman R.E., 1958) can lead to nanocomposites with reasonably high conductivity (Stankovich S. et al, 2006). Nanocomposites with similar electrical performance, however, can also be prepared with microwave exfoliated graphite (Kujawski M. et al, 2010). Most common, though, is graphite processing by a modified Hummer's method followed by thermal shock (Zheng W. and Wong S.-C., 2003).…”

Fabrication of a Miniature Paper-Based Electroosmotic Actuator

“…Thin film metal electrodes with serpentine shapes allow stretching [ 64 ], but they degrade under EO. Stretchable electrodes can also be made from composites containing conductive nanoparticles, such as carbon black (CB) [ 65 , 66 ] or exfoliated graphite (EG) [ 67 ], within an elastomeric host, but they have not previously been used for EO. Elastomer/EG composites are more stretchable, but CB composites were chosen for this work because the CB mixed more uniformly into the elastomers and large strains were not required.…”