Review of developments on polymers’ breakdown characteristics and mechanisms on a nanosecond time scale

Zhao, Linjie; Su, Jiancang; Liu, Chunliang

doi:10.1063/1.5110273

Cited by 15 publications

(6 citation statements)

References 80 publications

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“…But, this theme is not very simple to challenge because the experiments must be carried out for the polymer samples subjected to a high voltage. Different from the case of the application of a low electric field, which causes a slight change of the electron distribution in a molecule or an aggregation of molecules and the dielectric behavior can be deduced as well known, − the experiment under the application of middle or high electric field, which may give us information about the changes in the electric dipole orientation, the chain conformation, the aggregation structure of the chains, and even the higher-order structure composed of the crystalline and amorphous regions, is difficult to perform for the crystalline polymer substances because of an easy occurrence of the dielectric breakdown. , The experimental reports have been quite limited even when we search the literature carefully.…”

Section: Introductionmentioning

confidence: 99%

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

et al. 2021

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A high electric field was applied cyclically to poly(vinylidene fluoride) films, during which the simultaneous and time-resolved measurements of the two-dimensional wideangle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), and transmission-type Fourier transform infrared (FTIR) spectra were performed using a synchrotron X-ray radiation system. The inversion of the CF 2 dipole moments caused by the alternate change of the electric field vector direction was detected to occur around ±80−100 MV/m as estimated by the electricfield-strength dependence of the IR band intensity. On the other hand, the WAXD peaks were found to show the maximal intensities at 0 and ±250−300 MV/m. In these regions, the 001 reflection of the β form and the 002 reflection of the δ form changed the intensities remarkably and periodically. These experimental data were interpreted, not by the idea of a simple inversion motion of the rigid polar chains (the planar zigzag chains of the form β and the TGTG̅ chains of the α and δ forms) but by the more complicated couplings between the rotation and tilting motions of the chain segments, the cooperative T-G conformational exchanges, and the associated inversion motion of the CF 2 dipoles. The idea of the cooperative chain motions was supported by the density functional theory calculations performed under the external electric field. Different from the remarkable changes of the WAXD and FTIR data, the SAXS patterns did not show the detectable changes in these processes, indicating that the above-mentioned cooperative structural changes should occur in the crystalline regions with the stacked lamellar structure kept unchanged.

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Section: Introductionmentioning

confidence: 99%

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

et al. 2021

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“…When a high voltage was applied, the electric field is enough to accelerate the electrons to the ionization energy of the gas, and the ionized electrons would produce more electrons. As a result, increasingly more free electrons resulted in avalanche breakdown, 33,34 as shown in Figure 11B. This hypothesis was indirectly verified by the breakdown strength and the corresponding morphologies of breakdown sites in Figure 11C−E.…”

Section: ■ Results and Discussionmentioning

confidence: 58%

Dissolving and Regeneration of meta-Aramid Paper: Converting Loose Structure into Consolidated Networks with Enhanced Mechanical and Insulation Properties

Tan

Luo

Zhang

et al. 2021

ACS Appl. Mater. Interfaces

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Aramid paper has been widely used in high-voltage motors and transformers due to its excellent insulation property and thermal durability. However, the smoothness and chemical inertness of aramid fibers lead to a loose structure (voids) of aramid paper, which limits its potential applications in harsh environments, such as high-frequency and high-voltage circuits. This work reports a simple and efficient method to improve the mechanical and insulation properties of meta-aramid paper via controllable dissolving and regeneration of aramid fibers. To obtain a dense and robust structure, the pristine meta-aramid paper was immersed in a dimethyl sulfoxide/potassium hydroxide (DMSO/KOH) mixture to make aramid fibers swelled and dissolved, followed by regeneration in water vapor, eventually generating densified aramid paper with fewer voids and enhanced insulation and mechanical performance. Optimum conditions resulted in aramid paper with the best comprehensive performance, and the tensile strength, Young’s modulus, and electrical breakdown strength of the consolidated aramid paper were 22.85 MPa, 0.72 GPa, and 15.3 kV/mm, respectively, which were significantly higher than those of the pristine aramid paper (12.53 MPa, 0.41 GPa, and 8.36 kV/mm). Meanwhile, such treatment did not cause any chemical structure change, and thus it still retained the excellent thermal resistance (T d > 430 °C) of aramid fibers. This simple method can effectively regulate the surface porosity and the mechanical and breakdown strength of aramid paper, as well as provide a generic method for postprocessing and enhancing aramid paper.

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“…28 Regarding the influence of film thickness h on dielectric strength, it has been generally observed that inorganic dielectrics generally follow an inverse power-law dependence of dielectric strength on the film thickness, which is justified by the increased uniformity in thinner films and the presence of fewer defects. 29,30 However, for polymer films, the dielectric strength vs h relationship is not fully understood. 29 It has been shown that the dielectric strength of polymers such as poly(tetrafluoroethylene), poly(methyl methacrylate), polyethylene, etc.…”

Section: Significancementioning

confidence: 99%

Ultra-high Dielectric Strength and Capacitive Energy Density of Thin Entangled Glassy Polymer Films

Singh,

Nejat,

Douglas

et al. 2023

Preprint

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The influence of high-intensity electric fields on the stability of polymeric materials is a problem of interest in the design of next-generation energy storage and electronic devices, and for understanding the limits of stability of polymer films exposed to large electric fields generally. Here, we show that the dielectric strength of entangled glassy polymer films increases sharply as an inverse power-law of the film thickness h for “ultrathin” films below a micron in thickness. The dielectric strength enhancement in these polymer films can reach values as large as ≈ 2 GV/m in films thinner than 100 nm, but this large “finite-size” effect depends strongly on the polymer mass and sample aging time. Our enhanced dielectric breakdown with confinement can be consistently interpreted within a working model in which dielectric breakdown is taken to be an electric field-induced analog of previously reported mechanical yield enhancement in the same thickness range of glassy polymer films. As a proof of principle regarding applications, we utilized ultra-thin glassy polymer films of the type studied in our paper to fabricate polymeric nanocapacitors having ultra-high discharge energy densities (Udmax) as large as 27 J/cm3 and having efficiencies greater than 80 %. These efficiency values at comparable charge densities are significantly higher than those of competing ferroelectric polymer materials, and we anticipate that our observations will inspire the creation of practical high-energy density nanocapacitor devices for advanced energy storage applications.

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Review of developments on polymers’ breakdown characteristics and mechanisms on a nanosecond time scale

Cited by 15 publications

References 80 publications

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

High-Electric-Field-Induced Hierarchical Structure Change of Poly(vinylidene fluoride) as Studied by the Simultaneous Time-Resolved WAXD/SAXS/FTIR Measurements and Computer Simulations

Dissolving and Regeneration of meta-Aramid Paper: Converting Loose Structure into Consolidated Networks with Enhanced Mechanical and Insulation Properties

Ultra-high Dielectric Strength and Capacitive Energy Density of Thin Entangled Glassy Polymer Films

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