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.

Excellent comprehensive energy storage capabilities achieved in linear polymer composites via inserting acrylic rubber dielectric elastomers

2021 ◽  
Author(s):  
Jie Chen ◽  
Yifei Wang ◽  
Weixing Chen
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Polymer Composites ◽  
Linear Polymer ◽  
Dielectric Elastomers ◽  
Organic Film ◽  
Available Energy ◽  
Multilayer Composites ◽  
Potential Applications

Multilayer composites have the potential applications in organic film capacitors due to their excellent dielectric and breakdown characteristic. However, poor efficiency (η) and limited available energy density (Ue) of the...

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.

scholarly journals The Dispersion of Strong Field Dielectric Permittivity in (1-x)PMN-(x)PT Ceramics

2011 ◽  
Vol 56 (4) ◽  
pp. 1199-1203 ◽  
Author(s):  
P. Wawrzała ◽  
R. Skulski
Keyword(s):  
Dielectric Permittivity ◽  
Hysteresis Loop ◽  
Electric Fields ◽  
Strong Field ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Strong Electric Fields

The Dispersion of Strong Field Dielectric Permittivity in (1-x)PMN-(x)PT CeramicsWe propose the method of analysis of the dielectric permittivity measured in very strong electric fields. The method is based on the numeric calculations of derivative fromP - Ehysteresis loop. Such investigations have been performed for PMN-PT ceramics at various temperatures and frequencies. As a result we analyze the low frequency dispersion of the strong field dielectric permittivity.

Electrostatically Driven Creep in Viscoelastic Dielectric Elastomers

2013 ◽  
Vol 81 (5) ◽  
Author(s):  
Jin Wang ◽  
Thao D. Nguyen ◽  
Harold S. Park
Keyword(s):  
Finite Element ◽  
Relaxation Time ◽  
Element Model ◽  
Constitutive Law ◽  
Dielectric Elastomers ◽  
Inhomogeneous Deformation ◽  
Viscoelastic Relaxation ◽  
Constant Voltage ◽  
Dynamic Finite Element ◽  
Electromechanical Instability

We utilize a nonlinear, dynamic finite element model coupled with a finite deformation viscoelastic constitutive law to study the inhomogeneous deformation and instabilities resulting from the application of a constant voltage to dielectric elastomers. The constant voltage loading is used to study electrostatically driven creep and the resulting electromechanical instabilities for two different cases that have all been experimentally observed, i.e., electromechanical snap-through instability and bursting drops in a dielectric elastomer. We find that in general, increasing the viscoelastic relaxation time leads to an increase in time needed to nucleate the electromechanical instability. However, we find for these two cases that the time needed to nucleate the instability scales with the relaxation time.

scholarly journals Water-structuring molecules and nanomaterials enhance radiofrequency heating in biologically relevant solutions

2016 ◽  
Vol 52 (85) ◽  
pp. 12630-12633 ◽  
Author(s):  
Nadia C. Lara ◽  
Asad A. Haider ◽  
Jason C. Ho ◽  
Lon J. Wilson ◽  
Andrew R. Barron ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electric Fields ◽  
Biologically Relevant ◽  
Water Structuring ◽  
Radiofrequency Heating ◽  
Potential Applications ◽  
Cancer Hyperthermia

For potential applications in nano-mediated radiofrequency cancer hyperthermia, the nanomaterial under investigation must increase the heating of any aqueous solution in which it is suspended when exposed to radiofrequency electric fields.

scholarly journals Mechanoresponsive scatterers for high-contrast optical modulation

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Donghwi Cho ◽  
Haomin Chen ◽  
Jonghwa Shin ◽  
Seokwoo Jeon
Keyword(s):  
Energy Consumption ◽  
Electric Fields ◽  
Structural Parameters ◽  
Future Research ◽  
Great Promise ◽  
Design Strategies ◽  
Smart Windows ◽  
Advantages And Disadvantages ◽  
Potential Applications ◽  
External Stimuli

Abstract Smart chromatic materials with optical transmittances that can be modified by light scattering upon external stimuli are attracting extensive interest because of their appealing applications in smart windows, privacy protection, electronic displays, etc. However, the development of these scatterers, which are mostly activated by electric fields, is hindered by their intrinsic energy consumption, slow responses, and poor stability. Recently, mechanoresponsive scatterers based on a strain-driven reconfiguration of the surface or internal structure have emerged, featuring fast responses and a simple composition/fabrication. Because there is no energy consumption to maintain the transparency/opacity, this novel scheme for scatterers holds great promise to break the existing bottleneck. This article presents recent advances in the development of mechanoresponsive scatterers and compares different structural design strategies. The scatterers are categorized into 2D, 3D, and other types according to the dimensions of their functioning structures. The fabrication methods, mechanisms, and relationships between the structural parameters and optical modulating performances are discussed for each category. Next, the potential applications of these scatterers are outlined. Finally, the advantages and disadvantages of the mainstream 2D and 3D categories are summarized, followed by a perspective on future research directions.

scholarly journals Individual Split Au Square Ring for Surface Enhanced Raman and Hyper-Raman Scattering

2021 ◽  
Author(s):  
RuXin ZHang ◽  
Chaoling Du ◽  
Lu Sun ◽  
Wang XuRong ◽  
Xiang Li ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Electric Fields ◽  
Near Infrared ◽  
Scattered Light ◽  
Localized Surface Plasmon ◽  
Great Promise ◽  
Sensitivity Factor ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Potential Applications

Abstract In this paper, individual split Au square rings were numerically proposed as novel substrates for surface enhanced Raman and hyper-Raman scattering (SERS and SEHRS) simultaneously. The peak wavelengths of their localized surface plasmon resonances (LSPR) are revealed to fall in the near-infrared and visible light region, respectively, which are able to be finely tuned to match well with the wavelengths of the incident laser and hyper Raman scattered light beams. Their SEHRS and SERS performances along with electromagnetic (EM) field distributions are numerically investigated by finite element method. With the enhancement of near electric-fields generated by LSPRs, the maximum SEHRS and SERS enhancement factors are demonstrated to reach 1.22×1012 and 108, respectively. Meanwhile, the corresponding SERS based refractive-index (RI) sensitivity factor reaches as high as 258nm/RIU and 893nm/RIU, at visible and near-infrared wavelengths, respectively. The proposed structure is believed to hold great promise both for developing SEHRS, SERS and SERS based RI sensing substrates, which shows strong potential applications in nano sensing and enhanced Raman scattering.

2D pore-scale simulation of wide-band electromagnetic dispersion of saturated rocks

Geophysics ◽  
2007 ◽  
Vol 72 (3) ◽  
pp. F97-F110 ◽  
Author(s):  
Emmanuel Toumelin ◽  
Carlos Torres-Verdín
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Permittivity ◽  
Electric Fields ◽  
Electromagnetic Property ◽  
Wide Band ◽  
Geometrical Parameters ◽  
Pore Scale ◽  
Porous Rocks ◽  
Pore Connectivity ◽  
Scale Properties

Effective medium theories (EMTs) are invoked routinely to interpret multifrequency dispersions of dielectric permittivity and electrical conductivity of saturated rocks. However, EMTs exhibit limitations that substantially restrict their validity for petrophysical interpretation. For instance, pore connectivity is of significant interest in the study of subsurface reservoirs, but no existing EMT includes it as an explicit property in the analysis of kilohertz- to gigahertz-range dielectric measurements. We introduce a new approach to quantify the effects of pore geometry and connectivity on the kilohertz-gigahertz frequency dispersion of dielectric permittivity and electrical conductivity of clay-free porous rocks. This approach is based on the numerical solution of the internal electric fields within submicron-resolution pore maps constructed with grain and rock pixels. The discrepancy between the internal fields and electrical currents calculated for ahomogeneous scatterer and those calculated for a given pore map is minimized to yield the effective electrical conductivity and dielectric constant for that pore map. This minimization is performed independently for each frequency and is verified to agree implicitly with Kramers-Kronig's causality relationships. We show that EMTs only predict an average dispersion for given microscopic geometrical parameters (e.g., porosity, pore eccentricity), whereas individual realizations honoring the same parameters are associated with dispersion about average values predicted by EMTs. Unlike any EMT prediction, we show that pore connectivity plays a major role in both the shape and amplitude of wide-band electromagnetic property dispersions. The simulation procedure introduced in this paper provides a systematic method to assess the sensitivity of a multitude of pore-scale properties on the macroscopic wide-band dielectric dispersion of saturated rocks.

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