Effects of an ionic liquid and processing conditions on the β-polymorph crystal formation in poly(vinylidene fluoride)

Pickford, Tom; Xu, Gu; Heeley, Ellen L.; Wan, Chaoying

doi:10.1039/c9ce01051c

Cited by 42 publications

(27 citation statements)

References 53 publications

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“…Beside the acting as a plasticizing agent, ILs also play the role of the supplier of ionic charge carrier to significantly change polymer dielectric behavior 28,29 . These effects on crystallization and conductivity are related to amount of IL in the polymer electrolyte 25,[30][31][32] .…”

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confidence: 99%

The effect of thermal treatment on ac/dc conductivity and current fluctuations of PVDF/NMP/[EMIM][TFSI] solid polymer electrolyte

Sedlák

Gajdoš

Macků

et al. 2020

Sci Rep

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The experimental study deals with the investigation of the effect of diverse crystallinity of imidazolium ionic-liquid-based SPE on conductivity and current fluctuations. The experimental study was carried out on samples consisting of [EMIM][TFSI] as ionic liquid, PVDF as a polymer matrix and NMP as a solvent. After the deposition, the particular sample was kept at an appropriate temperature for a specific time in order to achieve different crystalline forms of the polymer in the solvent, since the solvent evaporation rate controls crystallization. The ac/dc conductivities of SPEs were investigated across a range of temperatures using broadband dielectric spectroscopy in terms of electrical conductivity. In SPE samples of the higher solvent evaporation rate, the real parts of conductivity spectra exhibit a sharper transition during sample cooling and an increase of overall conductivity, which is implied by a growing fraction of the amorphous phase in the polymer matrix in which the ionic liquid is immobilized. The conductivity master curves illustrate that the changing of SPEs morphology is reflected in the low frequency regions governed by the electrode polarization effect. The dc conductivity of SPEs exhibits Vogel–Fulcher–Tammann temperature dependence and increases with the intensity of thermal treatment. Spectral densities of current fluctuations showed that flicker noise, thermal noise and shot noise seems to be major noise sources in all samples. The increase of electrolyte conductivity causes a decrease in bulk resistance and partially a decrease in charge transfer resistance, while also resulting in an increase in shot noise. However, the change of electrode material results in a more significant change of spectral density of current fluctuations than the modification of the preparation condition of the solid polymer electrolyte. Thus, the contact noise is considered to contribute to overall current fluctuations across the samples.

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confidence: 99%

The effect of thermal treatment on ac/dc conductivity and current fluctuations of PVDF/NMP/[EMIM][TFSI] solid polymer electrolyte

Sedlák

Gajdoš

Macků

et al. 2020

Sci Rep

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“…DSC was used as a complement of the other identification techniques to further determine the interface hydrogen bonding effects, as shown in Figure 5 c,d. The endothermic peaks (melting temperature, T m ) of the PVDF-based films after the inclusion of the BTO, PDA-BTO or PFD-BTO NPs were 162.34, 161.37 and 160.93 °C, respectively, which are all lower than that of the as-printed pure PVDF film (163.13 °C), as shown in Figure 5 c. Many factors, such as the molecular structure, inclusion of fillers and interfacial interactions, could affect the T m of polymeric crystals [ 24 , 48 , 49 ]. Nevertheless, the lowering of T m may be attributed to the improvement in the β-phase content because the T m of the nonpolar α-phase is higher than that of the polar β-phase.…”

Section: Resultsmentioning

confidence: 97%

Boosting Performance of Self-Polarized Fully Printed Piezoelectric Nanogenerators via Modulated Strength of Hydrogen Bonding Interactions

Lim

2021

Nanomaterials

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Self-polarized piezoelectric devices have attracted significant interest owing to their fabrication processes with low energy consumption. Herein, novel poling-free piezoelectric nanogenerators (PENGs) based on self-polarized polyvinylidene difluoride (PVDF) induced by the incorporation of different surface-modified barium titanate nanoparticles (BTO NPs) were prepared via a fully printing process. To reveal the effect of intermolecular interactions between PVDF and NP surface groups, BTO NPs were modified with hydrophilic polydopamine (PDA) and hydrophobic 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) to yield PDA-BTO and PFD-BTO, respectively. This study demonstrates that the stronger hydrogen bonding interactions existed in PFD-BTO/PVDF composite film comparative to the PDA-BTO/PVDF composite film induced the higher β-phase formation (90%), which was evidenced by the XRD, FTIR and DSC results, as well as led to a better dispersion of NPs and improved mechanical properties of composite films. Consequently, PFD-BTO/PVDF-based PENGs without electric poling exhibited a significantly improved output voltage of 5.9 V and power density of 102 μW cm−3, which was 1.8 and 2.9 times higher than that of PDA-BTO/PVDF-based PENGs, respectively. This study provides a promising approach for advancing the search for high-performance, self-polarized PENGs in next-generation electric and electronic industries.

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“…13 Also, melting at high temperatures followed by controlled cooling produces piezoelectric lms with higher crystallinity and electroactivity. 14 The nonsolvent-induced phase separation (NIPS) process is largely employed in lm fabrication; however, immersion in the coagulation solvent creates lms with large voids and a nonuniform structure. Vaporinduced phase separation (VIPS) has an advantage over NIPS by immersing the cast lm aer exposing it to humidity for a certain time; this results in a uniform structure with very small pores and better crystallinity.…”

Section: Introductionmentioning

confidence: 99%

Method for fabricating highly crystalline polyvinylidene fluoride for piezoelectric energy-harvesting and vibration sensor applications

Raj

Abisegapriyan

Khandelwal

et al. 2022

Sustainable Energy Fuels

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Effects of an ionic liquid and processing conditions on the β-polymorph crystal formation in poly(vinylidene fluoride)

Abstract: The morphology, polar phase content and conductivity of PVDF nanofibres were enhanced by adding ionic substances to the electrospinning solution.

Cited by 42 publications

References 53 publications

The effect of thermal treatment on ac/dc conductivity and current fluctuations of PVDF/NMP/[EMIM][TFSI] solid polymer electrolyte

The effect of thermal treatment on ac/dc conductivity and current fluctuations of PVDF/NMP/[EMIM][TFSI] solid polymer electrolyte

Boosting Performance of Self-Polarized Fully Printed Piezoelectric Nanogenerators via Modulated Strength of Hydrogen Bonding Interactions

Method for fabricating highly crystalline polyvinylidene fluoride for piezoelectric energy-harvesting and vibration sensor applications

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