Advances in Polymeric Materials for Electromechanical Devices

Abstract

DEs especially exhibit potential for mimicking human muscles due to their high strain capacity and work density. [6] Polymers used for DEs often include siloxanes or acrylic elastomers, and the optimal DE actuators (DEA) in literature are surprisingly comprised of a commercial acrylic adhesive from 3 M. [7] However, these DEs require prestretching and large driving voltages to achieve large actuation strains, which limit their impact. The past decade has seen a plethora of research dedicated to finding materials to circumvent these limitations.Nafion has long served as the benchmark material for IPMCs due to its commercial availability and superior actuation performance at low voltages. Nafion actuators, however, have several drawbacks such as: low bending performance at low humidity, processing difficulties, and back relaxation. Due to these limitations, interest in new ionic polymers for IPMCs continues to grow in the literature. [8] This review aims to summarize the progress made in materials for EAP actuators over the past decade, focusing on IPMCs and DEAs, which comprise a significant fraction of the recent advances.

Isocyanate- and solvent-free synthesis of melt processible polyurea elastomers derived from urea as a monomer

“…This permittivity sits signicantly higher than many functionalized silicone and acrylics utilized in literature for DEs; however, this permittivity increase also corresponds with an increased Young's modulus compared to conventional DEA materials. 18 This composition also exhibits a relatively high dielectric loss when considering its application as a dielectric material. 30 Regardless, with more tuning, this composition may function effectively as a DEA due to its high permittivity and ability to achieve a large strain at break, and our future efforts will evaluate strategies for decreasing the dielectric loss while maintaining (or improving) the dielectric permittivity.…”

“…Polymers that exhibit high relative permittivity, or dielectric constant, nd use in energy storage devices such as capacitors and actuators. 17,18 Currently, polysiloxane and acrylic elastomers comprise much of the literature regarding dielectric elastomer actuators (DEA); however, these materials exhibit low relative permittivity values ranging from 3-4. Recent literature details methods for increasing permittivity of these materials through covalent attachment of dipolar substituents or blending with high permittivity llers, but these modications generally result in a corresponding increase in the Young's modulus, which is detrimental to DEA performance.…”

Siloxanes—Versatile Materials for Surface Functionalisation and Graft Copolymers

“…The operation of dielectric elastomer actuators [ 43 ] relies on the coulombic attraction of the oppositely charged electrodes, located on opposite sides of the elastomer material. This attraction induces a stress on the polymer in the direction of its thickness and results in an expansion of the elastomer in a plane parallel to the planes of the electrodes.…”

Can Polyelectrolyte Mechanical Properties be Directly Modulated by an Electric Field? A Molecular Dynamics Study

“…[ 1,2,7–9 ] Among these options, the ability to respond to electrical stimuli offers unique advantages in terms of on/off response time, ease of application within a bulk polymer, and relevance for energy conversion technologies. [ 10 ]…”