Polarization of thick polyvinylidene fluoride/trifluoroethylene copolymer films

Chan, Helen Lai Wa; Zhao, Ze; Kwok, Kin Wing; Choy, C. L.; Alquié, C.; Boué, C.; Lewiner, J.

doi:10.1063/1.363356

Cited by 34 publications

(26 citation statements)

References 32 publications

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“…[1][2][3][4][5] PVDF occurs in at least four different polymorphs. [6][7][8][9][10] These different crystal structures include the nonpolar R phase and the polar , γ, and δ phases.…”

Section: Introductionmentioning

confidence: 99%

The Role of Solution Phase Water on the Deposition of Thin Films of Poly(vinylidene fluoride)

2002

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Thin films of PVDF were deposited from a variety of solution conditions and examined by IR spectroscopy and scanning electron microscopy. Methods to rapidly assess the film thickness and the phase composition of PVDF films have been developed. In particular, the formation of the ferroelectric phase can be controlled by the composition of the solvent, notably the water content. Using a hydrated salt in the casting solvent reproducibly formed films with high phase content. However, the water also induces increased surface roughness in the deposited films. The nature of the PVDF films also is influenced by the kinetics of the evaporation process, and this was followed by IR spectroscopy. The rate constants depend on both the film thickness and the gas-phase humidity, indicating that solvent diffusion is an important contributor to both the bulk phase composition and the surface structure of the polymer films.

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“…[1][2][3][4][5] PVDF occurs in at least four different polymorphs. [6][7][8][9][10] These different crystal structures include the nonpolar R phase and the polar , γ, and δ phases.…”

Section: Introductionmentioning

confidence: 99%

The Role of Solution Phase Water on the Deposition of Thin Films of Poly(vinylidene fluoride)

2002

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“…Poly(vinylidene fluoride) (PVDF) has been extensively studied because it is a ferroelectric polymer 1–5. PVDF exists in at least three main crystalline modifications, designated as α (Form II), β (Form I), and γ (Form III), and in at least one minor phase, designated as δ (Form II′).…”

Section: Introductionmentioning

confidence: 99%

Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy

Benz¹,

Euler²

2003

J of Applied Polymer Sci

310

292

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A method with good precision has been developed to quantitatively measure the degree of ␣-, ␤-, and ␥ crystallinity in poly(vinylidene fluoride) (PVDF) by means of infrared spectroscopy. The phase composition of solutiondeposited PVDF films was found to be strongly influenced by the presence of hydrophilic residues on the silicon substrate, the relative humidity present at film deposition, the spatial position on the substrate, and the thermal treatment of the deposited film. Films produced on pristine surfaces gave predominantly ␣-phase PVDF, but when a layer of polar solvent (acetone or methanol) remained on the surface, the films produced were predominantly ␥ phase. Higher humidity promoted a higher fraction of ␥ crystallinity in the solution-deposited PVDF films. Solution-cast films had highly variable composition across the substrate, whereas spin-cast films were uniform. High-temperature annealing of PVDF films normally converts the polymer to the ␥ phase, but annealing the film while still attached to the silicon substrate inhibited this phase transformation. Low-temperature annealing of freestanding films led to a previously unreported thermal event in the DSC, a premelting process that is a kinetic event, assigned to a crystalline relaxation. Higher-temperature annealing gave a double endotherm, assigned to melting of different-sized crystalline domains.

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“…Trifluoroethylene residues in the copolymer, P(VDF-TrFE), act as steric hindrance stabilizers to form the β-phase 11 which minimizes the necessity for extra processing (i.e., physical stretching) to attain piezoelectric properties albeit such a post-process can further enhance piezoelectricity. 12 In this context, electrospinning is advantageous to produce high performance piezoelectric polymers because the technique intrinsically subjects the polymers to a high electric field. A charged polymer jet under an electric field is attracted to a collection plate, resulting in the formation of a fibrous structure whose dimensions are controlled from a few microns down to several nanometers in diameter.…”

Section: Introductionmentioning

confidence: 99%

Size-dependent piezoelectric and mechanical properties of electrospun P(VDF-TrFE) nanofibers for enhanced energy harvesting

et al. 2016

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Piezoelectricity-based energy harvesting from wasted mechanical energies has garnered an increasing attention as a clean energy source. Especially, flexible organic piezoelectric materials provide an opportunity to exploit their uses in the mechanically challenging areas where brittle inorganic counterparts have mechanical limitations. In this regard, electrospinning has shown its advantages of producing poly(vinylidene fluoride) (PVDF)-based nanofibrous structures without the necessity of a secondary processing to induce/increase piezoelectric properties. However, the effects of electrospun fiber dimension, one of the main morphological parameters in electrospun fibers, on piezoelectricity have not been fully understood. In this study, two dependent design of experiments (DOEs) were utilized to systematically control the dimensions of electrospun poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) to produce nanofibers having their diameter ranging from 1000 to sub-100 nm. Such a dimensional reduction resulted in the increase of piezoelectric responsible electroactive phase content and the degree of crystallinity. These changes in crystal structure led to approximately 2-fold increase in piezoelectric constant as compared to typical P(VDF-TrFE) thin films. More substantially, the dimensional reduction also increased the Young's modulus of the nanofibers up to approximately 80-fold. The increases in piezoelectric constant and Young's modulus collectively enhanced piezoelectric performance, resulting in the exponential increase in electric output of nanofiber mats when the fiber diameters were reduced from 860 nm down to 90 nm.Taken together, the results suggest a new strategy to improve the piezoelectric performance of electrospun P(VDF-TrFE) via optimization of their electromechanical and mechanical properties.

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Polarization of thick polyvinylidene fluoride/trifluoroethylene copolymer films

Cited by 34 publications

References 32 publications

The Role of Solution Phase Water on the Deposition of Thin Films of Poly(vinylidene fluoride)

The Role of Solution Phase Water on the Deposition of Thin Films of Poly(vinylidene fluoride)

Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy

Size-dependent piezoelectric and mechanical properties of electrospun P(VDF-TrFE) nanofibers for enhanced energy harvesting

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