Dielectric properties and electric breakdown strength of a subpercolative composite of carbon black in thermoplastic copolymer

Stoyanov, Hristiyan; Carthy, Denis N. Mc; Kollosche, Matthias; Kofod, Guggi

doi:10.1063/1.3154553

Cited by 109 publications

(94 citation statements)

References 23 publications

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“…(matching with the region I introduced previously) which is followed by a precipitous drop, a behavior which has been observed before (for a discussion, see Ref. 15). In region I, the breakdown strength is seen to decrease from 140 V/μm for the pure material to about 120 V/μm, a drop of just 14%.…”

Section: Resultssupporting

confidence: 51%

“…Sub-percolative approach based on dispersing conductive particle in the elastomer matrix lead to an increase in permittivity of several orders of magnitude, which has the advantage of minimal influence on the mechanical properties due to small amounts of filler required [16]. However, a serious drawback of the approach is the lowering of the electric breakdown strength of the composite, which offsets the high permittivity gains with respect to stored electrical energy [15]. A promising approach and the best so far is based on the dispersion of nano-clusters of highly polarizable molecules, in which the polarizable molecules are loaded into the polymer matrix [18], or directly blended from a liquid phase [13].…”

Section: Introductionmentioning

confidence: 97%

“…Another approach allowing reduction in the operating voltage, would be decreasing the thickness of the elastomer film. However due to the difficulties related with producing and handling of very thin elastomer films, the research interest has been focused mainly on developing elastomer materials with high permittivity [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Flexible enhanced energy density composites for dielectric elastomer actuators

Stoyanov

Kollosche

McCarthy

et al. 2010

Electroactive Polymer Actuators and Devices (EAPAD) 2010

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Dielectric elastomer actuators deform due to voltage-induced Maxwell-stress, which interacts with the mechanical properties of the material. Such actuators are considered for many potential applications where high actuation strain and moderate energy density comparable to biological muscle are required. However, the high voltage commonly required to drive them is a limitation, especially for biomedical applications. The high driving voltage can be lowered by developing materials with increased permittivity, while leaving the mechanical properties unaffected. Here, an approach to lowering the driving voltage is presented, which relies on a grafted nano-composite, in which conducting nanoparticles are integrated directly into a flexible matrix by chemical grafting. The conducting particles are π-conjugated soft macromolecules, which are grafted chemically to a polymer matrix flexible backbone. Dielectric spectroscopy, tensile mechanical analysis, and electrical breakdown strength tests were performed to fully characterize the electro-mechanical properties. Planar actuators were prepared from the resulting composites and actuation properties were tested in two different modes: constant force and constant strain. With this approach, it was found that the mechanical properties of the composites were mostly unaffected by the amount of nanoparticles, while the permittivity was seen to increase from 2.0 to 15, before percolation made further concentration increases impossible. Hence, it could be demonstrated that the socalled "optimum load" was independent from the permittivity (as expected), while the operating voltage could be lowered, or higher strains could be observed at the same voltage.

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Section: Resultssupporting

confidence: 51%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Flexible enhanced energy density composites for dielectric elastomer actuators

Stoyanov

Kollosche

McCarthy

et al. 2010

Electroactive Polymer Actuators and Devices (EAPAD) 2010

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show abstract

“…We investigated the permittivity and electric breakdown strength, to evaluate the applicability of this approach for DEA. Some of these results have already been presented elsewhere [23], here we have expanded the investigation with measurements of the Young's modulus, to show how an important figure of merit for evaluation of the improvement is affected by the sub-percolative composite approach.…”

Section: Introductionmentioning

confidence: 79%

Sub-percolative composites for dielectric elastomer actuators

et al. 2009

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Dielectric elastomer actuators (DEA) based on Maxwell-stress induced deformation are considered for many potential applications where high actuation strain and energy are required. However, the high electric field and voltage required to drive them limits some of the applications. The high driving field could be lowered by developing composite materials with high-electromechanical response. In this study, a sub-percolative approach for increasing the electromechanical response has been investigated. Composites with conductive carbon black (CB) particles introduced into a soft rubber matrix poly-(styrene-co-ethylene-co-butylene-co-styrene) (SEBS) were prepared by a drop-casting method. The resulting composites were characterized by dielectric spectroscopy, tensile tests, and for electric breakdown strength. The results showed a substantial increase of the relative permittivity at low volume percentages, thereby preserving the mechanical properties of the base soft polymer material. Young's modulus was found to increase with content of CB, however, due to the low volume percentages used, the composites still retain relatively low stiffness, as it is required to achieve high actuation strain. A serious drawback of the approach is the large decrease of the composite electric breakdown strength, due to the local enhancement in the electric field, such that breakdown events will occur at a lower macroscopic electric field.

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“…As reported previously, dielectric permittivity is a complex parameter and measurements made at low electric fields for composite materials can give misleading results due to increases in the dielectric loss (tan d) related to Maxwell-Wagner polarization or increased conductivity which leads to substantial decreases in the electric field that the material can support and thus greatly reducing overall performance. 23 The mechanical properties of the material were characterized using the same setup and actuator configuration under a dynamic load in the frequency range of 0.1 to 20 Hz at a strain of 1% (Fig. 2).…”

mentioning

confidence: 99%

Dielectric elastomer transducers with enhanced force output and work density

Stoyanov

Brochu

Niu

et al. 2012

Applied Physics Letters

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Efficient excitation of a monopole optical transducer for near-field recording J. Appl. Phys. 112, 043108 (2012) On the lifetime of plasmonic transducers in heat assisted magnetic recording J. Appl. Phys. 112, 034512 (2012) Development of a quasi-adiabatic calorimeter for the determination of the water vapor pressure curve Rev. Sci. Instrum. 83, 075114 (2012) A synthetic Brownian ratchet architecture for creating tailorable chemomechanical nanomachines

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Dielectric properties and electric breakdown strength of a subpercolative composite of carbon black in thermoplastic copolymer

Cited by 109 publications

References 23 publications

Flexible enhanced energy density composites for dielectric elastomer actuators

Flexible enhanced energy density composites for dielectric elastomer actuators

Sub-percolative composites for dielectric elastomer actuators

Dielectric elastomer transducers with enhanced force output and work density

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