Polar Elastomers as Novel Materials for Electromechanical Actuator Applications

Abstract

Dielectric elastomer actuators are stretchable capacitors capable of a musclelike actuation when charged. They will one day be used to replace malfunctioning muscles supposing the driving voltage can be reduced below 24 V. This focus here is on polar dielectric elastomers and their behavior under an electric field. Emphasis is placed on all the features that are correlated with the molecular structure, its synthetic realization, and its impact on properties. Regarding the polymer class, the focus, to some degree, is on polysiloxanes because of their attractively low glass transition temperatures. This enables introduction of highly polar groups to the backbone while maintaining soft elastic properties. The goal is to provide a few guidelines for future research in this emerging field that may be useful for those considering entering this fascinating endeavor. Because of the large number of materials available, a few restrictions in the selection have to be applied.

Artificial Muscles: Dielectric Elastomers Responsive to Low Voltages

“…Materials solutions to high dielectric permittivity elastomers include blending the elastomer with highly polarizable fillers or chemical modification with polar groups. Both approaches are however limited either by an increased stiffness or a reduced breakdown field, or both . Additionally, thin film formation turns challenging, especially for blends.…”

“…Additionally, thin film formation turns challenging, especially for blends. Chemical modification of polymers with polar groups is associated by a large increase in the glass transition temperature . It is therefore not surprising that only few polymers furnish low T g materials after chemical modification with polar groups.…”

“…Both approaches are however limited either by an increased stiffness or a reduced breakdown field, or both. [7,8] Additionally, thin film formation turns challenging, especially for blends. Chemical modification of polymers with polar groups is associated by a large increase in the glass transition temperature.…”

“…[2] A large variety of prototypes were constructed, which one day will find applications in automobiles, robotics, electronics, aerospace, medical products, and medicine. [3,4] While a large variety of insulating elastomers can be used as dielectric, [5][6][7][8][9] one issue associated with the DEA technology is the high driving voltage required for actuation, which is in the kV range. [10] Attempts to reduce the driving voltage include decreasing film thickness, reducing the elastic modulus, and increasing the conditions.…”

Triboelectric‐TFT Flip‐Flop for Bistable Latching of Dielectric Elastomer Actuators

“…Reduction of the DEA operation voltage could be obtained by decreasing the dielectric thickness [20,21] or by increasing the dielectric constant of the dielectric. [22] Our approach can be generalized to a DEA with a higher operation voltage if the HVTFT is made also to withstand higher drainsource voltage. [10] A cross-section of the device is shown in Figure 3e.…”