Effect of crystallization and anneal on thin films of vinylidene fluoride/trifluorethylene (VR<sub>2</sub>/F<sub>3</sub>E) copolymers

Bongianni, W.L.

doi:10.1080/00150199008211372

Cited by 7 publications

(1 citation statement)

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“…Note that the steric force due to a relatively larger proportion of the fluorine atoms makes P(VDF‐TrFE) a better choice than PVDF for this study, because it favors the crystallization of the electroactive β phase at room temperature after thermal treatment. [ 63 ] Simultaneously, thermal annealing can facilitate the tuning of porosity by providing sufficient kinetic energy for polymer chains to gradually fill the pores filled with air. Thus, less porous structures can be obtained with an increase in the annealing temperature.…”

Section: Resultsmentioning

confidence: 99%

Ambient Humidity‐Induced Phase Separation for Fiber Morphology Engineering toward Piezoelectric Self‐Powered Sensing

Lee

Kim

Lee

et al. 2022

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Electrospun polymeric piezoelectric fibers have a considerable potential for shape‐adaptive mechanical energy harvesting and self‐powered sensing in biomedical, wearable, and industrial applications. However, their unsatisfactory piezoelectric performance remains an issue to be overcome. While strategies for increasing the crystallinity of electroactive β phases have thus far been the major focus in realizing enhanced piezoelectric performance, tailoring the fiber morphology can also be a promising alternative. Herein, a design strategy that combines the nonsolvent‐induced phase separation of a polymer/solvent/water ternary system and electrospinning for fabricating piezoelectric poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE) fibers with surface porosity under ambient humidity is presented. Notably, electrospun P(VDF‐TrFE) fibers with higher surface porosity outperform their smooth‐surfaced counterparts with a higher β phase content in terms of output voltage and power generation. Theoretical and numerical studies also underpin the contribution of the structural porosity to the harvesting performance, which is attributable to local stress concentration and reduced dielectric constant due to the air in the pores. This porous fiber design can broaden the application prospects of shape‐adaptive energy harvesting and self‐powered sensing based on piezoelectric polymer fibers with enhanced voltage and power performance, as successfully demonstrated in this work by developing a communication system based on self‐powered motion sensing.

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Section: Resultsmentioning

confidence: 99%

Ambient Humidity‐Induced Phase Separation for Fiber Morphology Engineering toward Piezoelectric Self‐Powered Sensing

Lee

Kim

Lee

et al. 2022

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Double ferroelectric‐to‐paraelectric transition in 70/30 vinylidene fluoride‐trifluoro ethylene copolymer as revealed by dielectric spectroscopy

Ezquerra

Kremer

Baltà‐Calleja

et al. 1994

J Polym Sci B Polym Phys

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The variation of dielectric properties with temperature in the 1 kHz to 1 GHz frequency range for the 70/30 copolymer of vinylidene fluoride with trifluoroethylene has been associated to two processes: the β relaxation process associated with the glass transition of the amorphous phase and the ferroelectric‐to‐paraelectric crystal transition. The β process follows a Vogel‐Fülcher behavior exhibiting an anomaly in the vicinity of the crystal transition. Analysis of the ferroelectric‐to‐paraelectric Curie transition reveals the existence of a double relaxation maximum in the dielectric losses. Results have been interpreted in terms of the Havriliak‐Negami relaxation function. The variation of the relaxation strength and of the broadening parameter has been investigated as a function of temperature. The obtained results are discussed in terms of a two‐step phase transformation mechanism for the Curie transition: a first transition from the low temperature “all‐trans” ferroelectric phase to a more defective phase; a second transition from the latter phase to the final paraelectric structure. © 1994 John Wiley & Sons, Inc.

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Structure and properties of ferroelectric copolymers of poly(vinylidene fluoride)

Calleja

Arché²,

Ezquerra

et al. 1993

Structure in Polymers With Special Properties

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Effect of crystallization and anneal on thin films of vinylidene fluoride/trifluorethylene (VR₂/F₃E) copolymers

Cited by 7 publications

References 6 publications

Ambient Humidity‐Induced Phase Separation for Fiber Morphology Engineering toward Piezoelectric Self‐Powered Sensing

Ambient Humidity‐Induced Phase Separation for Fiber Morphology Engineering toward Piezoelectric Self‐Powered Sensing

Double ferroelectric‐to‐paraelectric transition in 70/30 vinylidene fluoride‐trifluoro ethylene copolymer as revealed by dielectric spectroscopy

Structure and properties of ferroelectric copolymers of poly(vinylidene fluoride)

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Effect of crystallization and anneal on thin films of vinylidene fluoride/trifluorethylene (VR2/F3E) copolymers

Cited by 7 publications

References 6 publications

Ambient Humidity‐Induced Phase Separation for Fiber Morphology Engineering toward Piezoelectric Self‐Powered Sensing

Ambient Humidity‐Induced Phase Separation for Fiber Morphology Engineering toward Piezoelectric Self‐Powered Sensing

Double ferroelectric‐to‐paraelectric transition in 70/30 vinylidene fluoride‐trifluoro ethylene copolymer as revealed by dielectric spectroscopy

Structure and properties of ferroelectric copolymers of poly(vinylidene fluoride)

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Effect of crystallization and anneal on thin films of vinylidene fluoride/trifluorethylene (VR₂/F₃E) copolymers