scholarly journals Self-Repairable, High Permittivity Dielectric Elastomers with Large Actuation Strains at Low Electric Fields

2015 ◽  
Vol 25 (16) ◽  
pp. 2467-2475 ◽  
Author(s):  
Simon J. Dünki ◽  
Yee Song Ko ◽  
Frank A. Nüesch ◽  
Dorina M. Opris
Keyword(s):  
Electric Fields ◽  
Dielectric Elastomers ◽  
High Permittivity

DESIGNING DIELECTRIC ELASTOMERS OVER MULTIPLE LENGTH SCALES FOR 21ST CENTURY SOFT MATERIALS TECHNOLOGIES

2017 ◽  
Vol 90 (2) ◽  
pp. 207-224 ◽  
Author(s):  
Daniel P. Armstrong ◽  
Richard J. Spontak
Keyword(s):  
Electric Fields ◽  
Thermoplastic Elastomer ◽  
Soft Materials ◽  
Dielectric Elastomers ◽  
Length Scales ◽  
Electric Stimulus ◽  
Profound Impact ◽  
Multiple Length Scales ◽  
Electromechanical Performance ◽  
Strain Cycling

ABSTRACT Dielectric elastomers (DEs) constitute an increasingly important category of electroactive polymers. They are in a class of generally soft materials that, upon exposure to an electric stimulus, respond by changing size, shape, or both. Derived from network-forming macromolecules, DEs are lightweight, robust and scalable, and they are capable of exhibiting giant electroactuation strains, high electromechanical efficiencies, and relatively low strain-cycling hysteresis over a broad range of electric fields. Due primarily to their attractive electromechanical attributes, DEs are of growing interest in diverse biomedical, (micro)robotic, and analytical technologies. Since the seminal studies of these electroresponsive materials (initially fabricated mainly from chemically cross-linked acrylic and silicone elastomers), advances in materials design over multiple length scales have resulted in not only improved electromechanical performance but also better mechanistic understanding. We first review the fundamental operating principles of DEs developed from conventional elastomers that undergo isotropic electroactuation and then consider more recent advances at different length scales. At the macroscale, incorporation of oriented fibers within elastomeric matrices is found to have a profound impact on electroactuation by promoting an anisotropic response. At the mesoscale, physically cross-linked thermoplastic elastomer gel networks formed by midblock-swollen triblock copolymers provide a highly tunable alternative to chemically cross-linked elastomers. At the nanoscale, the chemical synthesis of binetwork and bottlebrush elastomers permits extraordinarily enhanced electromechanical performance through targeted integration of inherently prestrained macromolecular networks.

Effect of Dielectric Imperfections on the Electroactive Deformations of Polar Dielectric Elastomers

2019 ◽  
Vol 86 (8) ◽  
Author(s):  
Yanhui Jiang ◽  
Yang Liu
Keyword(s):  
Dielectric Permittivity ◽  
Shear Modulus ◽  
Electric Fields ◽  
Nonlinear Deformation ◽  
Dielectric Elastomers ◽  
Inhomogeneous Deformation ◽  
Polar Dielectric ◽  
Polar Groups ◽  
Deformation Stability ◽  
Potential Applications

We find that the ratio of dielectric permittivity to shear modulus is linearly related to the number of polar groups per polymer chain in polar dielectric elastomers (PDEs). Our discovery is verified via computational modeling and validated by experimental evidences. Based on the finding, we introduce the new concept of dielectric imperfection (DI) and provide some physical insights into understanding it through demonstrating the large nonlinear deformation of PDEs with DIs under electric fields. The results show remarkable DI-induced inhomogeneous deformation and indicate that the size and dielectric permittivity of DIs have a significant impact on the deformation stability of PDEs under electric fields. With this concept, we propose some potential applications of PDEs with DIs.

scholarly journals Compatibilization of porphyrins for use as high permittivity fillers in low voltage actuating silicone dielectric elastomers

RSC Advances ◽  
2020 ◽  
Vol 10 (31) ◽  
pp. 18477-18486 ◽  
Author(s):  
Cody B. Gale ◽  
Michael A. Brook ◽  
Anne Ladegaard Skov
Keyword(s):  
Low Voltage ◽  
Dielectric Elastomers ◽  
High Permittivity

Derivatization of the porphyrin TPMP improves its dispersion in silicone dielectric elastomers, resulting in materials capable of achieving high actuations at low voltages.

Ultrahigh discharge efficiency and energy density achieved at low electric fields in sandwich-structured polymer films containing dielectric elastomers

2019 ◽  
Vol 7 (8) ◽  
pp. 3729-3736 ◽  
Author(s):  
Jie Chen ◽  
Yifei Wang ◽  
Xinwei Xu ◽  
Qibin Yuan ◽  
Yujuan Niu ◽  
...  
Keyword(s):  
Energy Density ◽  
Electric Fields ◽  
Polymer Films ◽  
High Efficiency ◽  
Dielectric Elastomers ◽  
Low Field ◽  
Discharge Efficiency

A sandwich-structured film is capable of an ultra-high efficiency of 89% with an energy density of 11.8 J cm−3 at a low field of 300 MV m−1.

scholarly journals Synthesis of solvent-free processable and on-demand cross-linkable dielectric elastomers for actuators

2019 ◽  
Vol 7 (39) ◽  
pp. 12139-12150 ◽  
Author(s):  
Philip Caspari ◽  
Frank A. Nüesch ◽  
Dorina M. Opris
Keyword(s):  
Thin Films ◽  
Solvent Free ◽  
Dielectric Elastomers ◽  
High Permittivity ◽  
Electric Stimulus ◽  
On Demand ◽  
Solvent Free Synthesis

On-demand and solvent-free synthesis of high permittivity polysiloxane elastic thin films responsive to an electric stimulus is presented.

scholarly journals Mode jumping of split-ring resonator metamaterials controlled by high-permittivity BST and incident electric fields

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiaojian Fu ◽  
Xinxi Zeng ◽  
Tie Jun Cui ◽  
Chuwen Lan ◽  
Yunsheng Guo ◽  
...  
Keyword(s):  
Electric Fields ◽  
Ring Resonator ◽  
Split Ring Resonator ◽  
Split Ring ◽  
High Permittivity

Enhancing the Electro-Mechanical Response of Maxwell Stress Actuators

2008 ◽  
Vol 61 ◽  
pp. 46-53 ◽  
Author(s):  
Giuseppe Gallone ◽  
Federico Carpi ◽  
Fabia Galantini ◽  
Danilo De Rossi ◽  
Giovanni Levita
Keyword(s):  
Electric Fields ◽  
Mechanical Response ◽  
Particulate Composites ◽  
Dielectric Elastomers ◽  
New Materials ◽  
Electromechanical Properties ◽  
Essential Requirement ◽  
Tensile Elastic Modulus ◽  
High Electric Fields ◽  
Ceramic Fillers

The need for high electric fields to drive dielectric elastomers is still retaining their diffusion as actuators in some areas of potential application, as in the case of biomedical disciplines. The development of new materials offering superior electromechanical properties is thus an essential requirement in order to effectively reduce the driving fields. In this light, the present work is aimed to enhance the electromechanical properties of two silicone and polyurethane based dielectric elastomers, both by making particulate composites with high-permittivity ceramic fillers, and by blending with a highly polarisable polymeric phase. Due to a consequent worsening of the mechanical properties, pure composite architectures yielded only limited results on the overall electromechanical response. With the blend approach, instead, both an increase of the dielectric permittivity and an unexpected reduction of the tensile elastic modulus were observed, leading to an overall increase of the electromechanical response. In any case, a key role appears to be played by the nature and intensity of polarisation phenomena arising at interfaces between different phases.

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