High-Strain Actuator Materials Based on Dielectric Elastomers

Abstract

Dielectric elastomers are a new class of actuator materials that exhibit excellent performance. The principle of operation, as well as methods to fabricate and test these elastomers, is summarized here. The Figure is a sketch of an elastomer film (light gray) stretched on a frame (black) and patterned with an electrode (mid‐gray). Upon applying a voltage, the active portion of the elastomer expands and the strain can easily be measured optically.

Low moduli elastomers with low viscous dissipation

“…Therefore the bimodal heterogeneous network will reinforce itself at large strains and hence the mechanical breakdown strength may become very large as long as the breakdown strength of the material surrounding the 75 clusters is larger than the strength needed to initiate the deformation of the clusters. While several types of EAPs have been investigated [5][6][7][8] most effort has been put into dielectric elastomers (DE), which have been shown to be particularly attractive for large strain and high-power 80 applications [9][10][11] . Silicone and acrylic based elastomers are the most commonly used material as EAPs.…”

“…In Figure 8 the elastic behaviour of two chemically identical networks prepared by the two different reaction schemes are 10 shown. Elastic moduli of 88 KPa (1s-4p) and 19 KPa (2s-4p) are obtained with no significant viscous dissipation in the investigated frequency regime.…”

“…The handability of the bimodal networks is also favored to that of the unimodal networks with identical elastic moduli due to the nonsticky nature of the bimodal networks 10 where in contrast the unimodal networks will be extremely sticky. The bimodal networks have sufficiently high tear strength to be used in microfabrication as they can easily be removed from the spin coater even for very thin films.…”

Monodirectional Positioning Using Dielectric Elastomers

“…When an electric potential difference is applied across the polymeric film, coated with electrodes on both sides, a compressive stress, parallel to the electric field, is generated and, consequently, the material is compressed in thickness and expands in planar directions. In order to permit this deformation the electrodes in an EAP actuator must be compliant because the elastomeric polymers are essentially incompressible in volume and so when the polymeric film is compressed in thickness, it must expand in area [4]. Mechanical actuation can be obtained by the compressive stress which causes a compression along the thickness of the material and the consequent planar expansion of the dielectric elastomer.…”

Investigation on the viscoelastic behaviors of a circular dielectric elastomer membrane undergoing large deformation

“…12,13 To address such issues and reveal the electromechanical behaviors of DEs, a number of theoretical or experimental investigations were reported in recent years. [14][15][16][17][18][19][20][21][22][23][24][25][26] The existing investigations mostly relate to the time-independent elastic behaviors of the DEs. However, most DEs are rubber-like materials and they often involve in time-dependent, dissipative processes, such as conductive relaxation, dielectric relaxation and viscoelastic relaxation.…”