Improvement of actuation performance of dielectric elastomers by barium titanate and carbon black fillers

Abstract

Dielectric elastomers are promising materials for actuators resembling human muscle. Among elastomers, acrylic rubbers (ACM) have shown good actuation performance but its use is limited by the high operating voltages required. The present work demonstrates that simultaneous incorporation of nanostructured carbon black and dielectric fillers offers an increase in a dielectric permittivity and a suitable modulus of the elastomers matrix, enabling an improved electro-mechanical actuation performance at low voltages. By the use of reinforcing carbon black and barium titanate in an acrylic elastomer matrix a sixfold increase in the dielectric permittivity was realized. A fine tuning of the actuation stress and, consequently, actuation strain can be done by a judicial selection of the different filler concentrations in the soft rubber matrix. Finally, a synergistic effect of the fillers was observed in the improved actuation performance of the developed materials. This work may pave the way to design dielectric elastomers for actuator fabrication.

Polymer bilayers with enhanced dielectric permittivity and low dielectric losses by Maxwell–Wagner–Sillars interfacial polarization: Characteristic frequencies and scaling laws

“…Polymeric materials with high values of the dielectric permittivity represent an important class of materials, with numerous applications in various fields of research and technology, such as for instance energy storage, sensors, organic electronics, actuators, and so forth . Many efforts have been dedicated to enhance dielectric properties of polymeric materials . However, low dielectric permittivity of the polymeric materials still poses a challenge.…”

“…[9][10][11][12][13][14][15][16] Many efforts have been dedicated to enhance dielectric properties of polymeric materials. [16][17][18][19][20][21][22][23][24][25][26] However, low dielectric permittivity of the polymeric materials still poses a challenge. A conventional process typically used to increase the dielectric permittivity is by introducing electrical conductivity or incorporating conductive fillers into the polymer matrix to form a composite.…”

Enhancing dynamic actuation performance of dielectric elastomer actuators by tuning viscoelastic effects with polar crosslinking

“…2a. This phenomenon is typically related to dielectric relaxation, in which the polar groups on the polymer chains are unable to keep up with the alternating current, resulting in a loss of contribution to the dielectric permittivity 14,15,19 .…”

“…Hence, a large number of studies have focused on increasing the dielectric constant for improved actuation performance of DEAs, thereby achieving a higher area strain and work density. The general approaches that have often been investigated include the addition of ceramic particles with high dielectric permittivity 11,12 , the addition of conductive nanofillers 13,14 and chemical modification to introduce polar groups 15,16 . Alternatively, DEAs have been prestretched to reduce the effects of viscoelasticity.…”

Remarkably improved electromechanical actuation of polyurethane enabled by blending with silicone rubber

“…1,4,8,10 To conquer the challenge, many researchers have dedicated to fabricating elastomers with enhanced dielectric permittivity to improve the electrostatic pressure. 8 Various ceramics with high dielectric permittivity, 11,12 conductive nanomaterials, 13,14 and organic strong polar molecules [15][16][17] have been chemically/physically incorporated into the elastomers. Though the actuation of DEAs can be improved in some extent, the increase in elastic modulus and severe deterioration in dielectric strength limit the practical applications of such elastomers.…”