Thermally stimulated currents in polyvinylidene fluoride. I. Unstretched alpha -form PVDF

Mizutani, Teruyoshi; Yamada, Tatsuro; Ieda, Masayuki

doi:10.1088/0022-3727/14/6/022

Cited by 49 publications

(26 citation statements)

References 25 publications

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“…30 Known from past literature is that there are four dominant peaks in a TSC curve of poled PVDF; two corresponding to the relaxation of polarized dipoles and two due to trapped charge in the material. 31 The spectral peaks measured here agree with the literature, clearly showing four dominant peaks, however the current discharged is much greater than those reported for pure PVDF.…”

Section: B Internal Charge Testingsupporting

confidence: 89%

“…%, the piezoelectric coefficient d 31 can be enhanced to double that of pure PVDF. This is achieved through a multi-mechanistic enhancement involving the seeding of crystalline sites, creation of internal charge, increased polarization, and the optimization of Young's modulus and dielectric constant.…”

Section: Discussionmentioning

confidence: 98%

“…As shown in Table I, the SWNT composites reach a maximum d 31 While the d 31 coefficient provides some insight into the charge generated per unit applied force, the electromechanical coupling factor, k, is a measure of the efficiency of energy conversion, and can be expressed as:…”

Section: Mechanical Characteristicsmentioning

confidence: 99%

“…In Eq. (2), if one assumes a constant d 31 , the k 31 is proportional to the square of the Y and inversely proportional to e r . Thus, one then would expect that by increasing the Y and decreasing e r , a very electromechanically efficient material can be realized.…”

Section: Mechanical Characteristicsmentioning

confidence: 99%

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Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites

Baur

DiMaio

McAllister

et al. 2012

Journal of Applied Physics

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The piezoelectric performance of polyvinylidene fluoride (PVDF) is shown to double through the controlled incorporation of carbon nanomaterial. Specifically, PVDF composites containing carbon fullerenes (C 60 ) and single-walled carbon nanotubes (SWNT) are fabricated over a range of compositions and optimized for their Young's modulus, dielectric constant, and d 31 piezoelectric coefficient. Thermally stimulated current measurements show a large increase in internal charge and polarization in the composites over pure PVDF. The electromechanical coupling coefficients (k 31 ) at optimal loading levels are found to be 1.84 and 2 times greater than pure PVDF for the PVDF-C 60 and PVDF-SWNT composites, respectively. Such property-enhanced nanocomposites could have significant benefit to electromechanical systems employed for structural sensing, energy scavenging, sonar, and biomedical imaging. V C 2012 American Institute of Physics.

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Section: B Internal Charge Testingsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 98%

Section: Mechanical Characteristicsmentioning

confidence: 99%

Section: Mechanical Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites

Baur

DiMaio

McAllister

et al. 2012

Journal of Applied Physics

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show abstract

“…In contrast to linear dielectrics, ferroelectric PVDF has the potential to achieve a high energy density because of its high dielectric constant and high DC electric breakdown strength. [9][10][11][12][13][14][15][16] However, the polar crystal structure also results in high dielectric and ferroelectric losses (tan δ of nearly 0.02 at 1 kHz at ambient temperature [ 17 ] ) and a slow discharge speed.…”

Section: Introductionmentioning

confidence: 99%

Confined Ferroelectric Properties in Poly(Vinylidene Fluoride‐co‐Chlorotrifluoroethylene)‐graft‐Polystyrene Graft Copolymers for Electric Energy Storage Applications

Guan¹,

Yang²,

Wang³

et al. 2011

Adv Funct Materials

139

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Dielectric polymer film capacitors having high energy density, low loss and fast discharge speed are highly desirable for compact and reliable electrical power systems. In this work, we study the confined ferroelectric properties in a series of poly(vinylidene fluoride‐co‐chlorotrifluoroethylene)‐graft‐polystyrene [P(VDF‐CTFE)‐g‐PS] graft copolymers, and their potential application as high energy density and low loss capacitor films. Thin films (ca. 20 μm) are prepared by different processing methods, namely, hot‐pressing or solution‐casting followed by mechanical stretching at elevated temperatures. After crystallization‐induced microphase separation, PS side chains are segregated to the periphery of PVDF crystals, forming a confining interfacial layer. Due to the low polarizability of this confining PS‐rich layer at the amorphous–crystalline interface, the compensation polarization is substantially decreased resulting in a novel confined ferroelectric behavior in these graft copolymers. Both dielectric and ferroelectric losses are significantly reduced at the expense of a moderate decrease in discharged energy density. Our study indicates that the best performance is achieved for a P(VDF‐CTFE)‐g‐PS graft copolymer with 34 wt‐% PS; a relatively high discharged energy density of approximately 10 J cm−3 at 600 MV m−1, a low dielectric loss (tanδ = 0.006 at 1 kHz), and a low hysteresis loop loss (17.6%) at 550 MV m−1.

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Space-charge-limited conduction in vacuum-deposited PVDF films

Bodhane

Shirodkar

1999

J. Appl. Polym. Sci.

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Current-voltage characteristics of poly(vinylidene fluoride) (PVDF) films fabricated on glass substrates by thermal evaporation technique in the metal-polymermetal sandwich configuration were studied. The vacuum-deposited PVDF films were predominantly of ␣ form. However, when subjected to high-voltage, short-duration singular pulse, it possibly resulted in mixed ␣ ϩ ␤ form. The I-V curves of such films display the low-field ohmic region and the high-field square-law region. The current versus thickness curves in the square-law region and the transition voltage, V tr , versus thickness curves indicate the conduction process to be space-charge-limited. The analyses of the current-voltage characteristics indicated the presence of uniformly distributed high-trapping carrier densities on the order of 10 24 m Ϫ3 eV Ϫ1 with average activation energy of 0.263 eV.

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Thermally stimulated currents in polyvinylidene fluoride. I. Unstretched alpha -form PVDF

Cited by 49 publications

References 25 publications

Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites

Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites

Confined Ferroelectric Properties in Poly(Vinylidene Fluoride‐co‐Chlorotrifluoroethylene)‐graft‐Polystyrene Graft Copolymers for Electric Energy Storage Applications

Space-charge-limited conduction in vacuum-deposited PVDF films

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