Structural modifications in stretch‐induced crystallization in PVDF films as measured by small‐angle X‐ray scattering

Chinaglia, Dante Luís; Grégório, Rinaldo; Vollet, Dimas R.

doi:10.1002/app.35684

Cited by 19 publications

(12 citation statements)

References 30 publications

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“…Figure (a) shows the FTIR spectra of the samples prepared through solution casting. When the content of the BT nanoparticles increased, the peaks of the β‐phase (i.e., 839, 512, and 437 cm −1 ) became stronger than the α‐phase peaks, suggesting that introducing BT nanoparticles could promote the formation of β‐phase crystals . These results also showed that polymer chains were aligned on the surface of the BT particles in the TTTT conformation and, therefore, in the β‐phase, produced a strong interaction between the CH 2 of the PVDF chains and the BT…”

Section: Resultsmentioning

confidence: 82%

Crystallinity and morphology of barium titanate filled poly(vinylidene fluoride) nanocomposites

Gong

Chen

Tang

et al. 2018

J of Applied Polymer Sci

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In this study, crystallization behavior and micromorphology of barium titanate (BaTiO3, or BT) filled poly(vinylidene fluoride) (PVDF) nanocomposites were investigated based on Fourier‐transform infrared spectroscopy (FTIR), polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X‐ray diffractometry (XRD). BT/PVDF nanocomposite films with different concentrations of BT nanoparticles were prepared by solution casting method. The results revealed that the electrical conductivity and Seebeck coefficient of PVDF were improved by the incorporation BT nanoparticles. When 2 wt % of BT was loaded into the PVDF matrix, it mediated the β‐phase crystallization in PVDF. Furthermore, the β‐phase crystals could be transformed into α‐phase after the samples were isothermally crystallized at 155 °C for 20 min. The results of DSC and POM suggest that BT nanoparticles could act as nucleation agents, promoting the crystallization activity of PVDF in a nonisothermal crystallization process. The crystal phase is influential to the electrical properties of PVDF, therefore the findings of this study are useful for the development of new applications based on BT/PVDF nanocomposites, such as high‐performance thermoelectric devices or systems. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46877.

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Section: Resultsmentioning

confidence: 82%

Crystallinity and morphology of barium titanate filled poly(vinylidene fluoride) nanocomposites

Gong

Chen

Tang

et al. 2018

J of Applied Polymer Sci

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“…40 So, the real amorphous region thickness L 0 a can be calculated as: Fig. When calculating the slope, the boundaries of the high-q region should be q > 1/l, here l is the minimal thickness of the L c or the L a .…”

Section: Resultsmentioning

confidence: 99%

In situ study of the annealing process of a polyethylene cast film with a row-nucleated crystalline structure by SAXS

Chen

Cai

et al. 2015

RSC Adv.

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An in situ annealing process of a polyethylene cast film with a row-nucleated crystalline structure was followed using a SAXS setup equipped with a temperature-controlling unit. The annealing temperatures were set at 105 C, 115 C and 125 C, respectively. It was found that after annealing for 7200 s, the long period, crystalline thickness, the real amorphous layer thickness and diffuse transition layer thickness were increased, whereas the linear crystallinity didn't show a pronounced change. Compared with those at 105 C and 115 C, annealing at 125 C resulted in an apparent increase of the long period and crystalline thickness, as well as the crystalline thickening rate. During the initial annealing stage, the crystalline thickness was increased apparently. After annealing for 1800 s, the crystalline thickness versus annealing time curve showed a wave-like shape, due to the occurrence of melting and recrystallization behavior, which could not be observed during the early annealing stage. The initial crystalline thickness increase was mainly due to the crystallization of some tie chains in the amorphous region, as well as a small transformation of the diffuse transition layer into the crystalline region. The crystalline orientation degree based on the width of the SAXS patterns was improved apparently when the annealing temperature was around the maximum crystalline temperature. This work clarified the increase of crystalline thickness induced by annealing a polyethylene film with a row-nucleated crystalline structure. Fig. 11 The azimuthal scans of SAXS patterns (a) and full width at half maximum (FWHM) change (b) during annealing. Fig. 12 The schematic of lamellae thickening at 105, 115 and 125 C.This journal is

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“…This phenomenon is attributed to high electric poling and mechanical stretching during electrospinning process. The applied electric eld and stretching generally have a positive effect on the transformation of amorphous phase to polar β phase [30]. In Fig.…”

Section: Crystalline Structurementioning

confidence: 91%

“…Besides, the inset of Fig. 3(e) is the zoom-in view of one single ber and the typically pillar wrinkled surface is generally helpful to piezoelectric outputs [30].…”

Section: Fibers Morphology and Device Structurementioning

confidence: 99%

Porous, Multi-layered Piezoelectric Composites Based on Highly Oriented Pzt/pvdf Electrospinning Fibers for High-performance Piezoelectric Nanogenerators

Du¹,

Zhou²,

Zhang³

et al. 2021

Preprint

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Piezoelectric nanogenerators (PENGs) that can harvest mechanical energy from ambient environment have broad prospects for multi-functional applications. Here, multi-layered piezoelectric composites with a porous structure based on highly oriented PZT/PVDF electrospinning fibers are prepared via a laminating method to construct high-performance PENGs. PZT particles as piezoelectric reinforcing phases are embedded in PVDF fibers and facilitate the formation of polar β phase in PVDF. The multi-layered, porous structure effectively promotes the overall polarization and surface bound charge density, resulting in highly efficient electromechanical conversion. The PENG based on 10 wt.% PZT/PVDF composite fibers with a 220 µm film thickness output an optimal voltage of 62.0 V and a power of 136.9 μW, which is 3.4 and 6.5 times the voltage and power of 10wt.% PZT/PVDF casting film-based PENG, respectively. Importantly, the PENG shows a high sensitivity of 12.4 VN-1, presenting a significant advantage in comparison to PENGs with other porous structures. In addition, the composites show excellent flexibility with a Young’s modulus of 227.2 MPa and an elongation of 262.3%. This work shows great potential application of piezoelectric fiber composites in flexible energy harvesting devices.

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Structural modifications in stretch‐induced crystallization in PVDF films as measured by small‐angle X‐ray scattering

Cited by 19 publications

References 30 publications

Crystallinity and morphology of barium titanate filled poly(vinylidene fluoride) nanocomposites

Crystallinity and morphology of barium titanate filled poly(vinylidene fluoride) nanocomposites

In situ study of the annealing process of a polyethylene cast film with a row-nucleated crystalline structure by SAXS

Porous, Multi-layered Piezoelectric Composites Based on Highly Oriented Pzt/pvdf Electrospinning Fibers for High-performance Piezoelectric Nanogenerators

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