Formation of piezoelectric<i>β</i>-phase crystallites in poly(vinylidene fluoride)-graphene oxide nanocomposites under uniaxial tensions

Jiang, Zhiyuan; Zheng, Guang; Zhan, Ke; Han, Zhuo; Yang, Jun

doi:10.1088/0022-3727/48/24/245303

Cited by 23 publications

(21 citation statements)

References 21 publications

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“…The β phase of PVDF could be developed by different techniques such as adding chemicals and mechanical stretching or both of them . Researches proved that GO could basically establish β phase nucleation of PVDF . The intensity of this phase was also increased in patterns of both PVDF and M‐PVDF based MMMs.…”

Section: Resultsmentioning

confidence: 99%

Effective gas separation through graphene oxide containing mixed matrix membranes

Feijani

Tavassoli

Mahdavi

et al. 2018

J of Applied Polymer Sci

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In the present study, graphene oxide (GO) was incorporated into poly(vinylidene fluoride) (PVDF) and chemically modified PVDF (M-PVDF) to prepare mixed matrix membranes (MMMs) for gas separation application. Performed analyses proved appropriate dispersion of exfoliated GO sheets in polymer matrices and sufficient compatibility at the interfacial phases. M-PVDF based MMMs were thermally and mechanically more stable relative to the PVDF-based MMMs. The oxygen containing functional groups in M-PVDF was probably the main reason for this more stability. PVDF/GO MMMs rendered low gas permeability and high selectivity. Both impermeable GO sheets and crystalline phases of PVDF were responsible for such behavior. On the other hand, interestingly gas permeability of M-PVDF/GO MMMs was enhanced while no substantial decline was recorded in gas selectivity. For instance, He and CO 2 permeability was increased 12.46% and 25.89%, respectively, compared to the pure PVDF membrane. This behavior originated from functional groups of M-PVDF and the interaction of these groups with GO sheets. Since GO often amplified gas barrier properties of polymers, such increscent would be appreciable.

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Section: Resultsmentioning

confidence: 99%

Effective gas separation through graphene oxide containing mixed matrix membranes

Feijani

Tavassoli

Mahdavi

et al. 2018

J of Applied Polymer Sci

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“…The interaction between the functional groups of GO and the −CF 2 or −CH 2 groups of PVDF are responsible for this phase transformation. 43 For example, El Achaby et al enhanced the β phase by incorporating GO in PVDF using the solvent casting method. This was attributed to the specific interaction between −C=O of GO and CF 2 of PVDF.…”

Section: Resultsmentioning

confidence: 99%

Piezoelectric Response in Electrospun Poly(vinylidene fluoride) Fibers Containing Fluoro-Doped Graphene Derivatives

2018

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Herein, graphene oxide (GO) was suitably functionalized to obtain carboxylated and fluorinated GO (GOCOOH and GOF) derivatives, respectively, via the Hunsdiecker reaction. Electrospun mats of poly(vinylidene fluoride) (PVDF)/GO, PVDF/GOCOOH, and PVDF/GOF fibers were then prepared by electrospinning from well-dispersed GO derivatives. The piezoelectric coefficient ( d 33 ), as measured using piezoelectric force measurement (PFM), enhanced by more than 2 folds with respect to the control PVDF spun mat. The piezoelectric coefficient though enhanced upon the addition of GO and GOCOOH, however, enhanced significantly in the case of GOF. For instance, a drastic increase in piezoelectric response from 30 pm V –1 (electrospun neat PVDF) to 63 pm V –1 (for electrospun PVDF/GOF) was observed as revealed from PFM results. The phase transformation in these fibers was systematically investigated by various techniques such as Fourier transform infrared spectroscopy (FTIR), wide angle X-ray diffraction (XRD), Raman spectroscopy, and PFM. FTIR and XRD results revealed that the electrospun fiber mats showed predominantly β-PVDF. Interestingly, the highest β content was obtained in the presence of GOF. The drastic enhancement in β phase is due to the presence of highly electronegative fluorine. The addition of GOCOOH and GOF in PVDF not only increases the polar β phase but also changes the piezoelectric response significantly. More interestingly, PVDF/GOF films exhibited higher energy density and dielectric permittivity when compared with the control PVDF samples. These findings will help guide the researchers working in this field from both theoretical understanding and practical view point for energy storing device and charge storage electronics.

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“…The apparent activation energy E a of β relaxation for the GAsPVDF-GO10% and GAsPVDF-10% samples is 0.16 eV and 0.29 eV, respectively. Because E a of β relaxation for the GAsPVDF-GO10% sample is consistent with that (~0.15 eV) for PVDF-GO composite films [23] and is different with that (~0.09 eV) for pure PVDF films [18], it is envisaged that GOs are incorporated into the PVDF films in GAsPVDF-GO10% samples.…”

Section: Anelastic Analysis On the Interfacesmentioning

confidence: 65%

“…Since the additions of GOs in PVDF enhance the polar crystalline phase of PVDF [17,18,23], the films in GAsPVDF-GOx samples have less amorphous structures than those in GAsPVDF-x samples. Comparison between the P β peak temperatures for the GAsPVDF-GO10% samples and the GAsPVDF-10% samples could provide further evidence, as shown in Figure 9b and 9c, respectively.…”

Section: Anelastic Analysis On the Interfacesmentioning

confidence: 99%

Mechanical and electro-mechanical properties of three-dimensional nanoporous graphene-poly(vinylidene fluoride) composites

Zheng

Jiang²,

Han³

et al. 2016

Express Polym. Lett.

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Abstract. Three-dimensional nanoporous graphene monoliths are utilized to prepare graphene-poly(vinylidene fluoride) nanocomposites with enhanced mechanical and electro-mechanical properties. Pre-treatment of the polymer (poly(vinylidene fluoride), PVDF) with graphene oxides (GOs) facilitates the formation of uniform and thin PVDF films with a typical thickness below 100 nm well coated at the graphene nano-sheets. Besides their excellent compressibility, ductility and mechanical strength, the nanoporous graphene-PVDF nanocomposites are found to possess high sensitivity in strain-dependent electrical conductivity. The improved mechanical and electro-mechanical properties are ascribed to the enhanced crystalline β phase in PVDF which possesses piezoelectricity. The mechanical relaxation analyses on the interfaces between graphene and PVDF reveal that the improved mechanical and electro-mechanical properties could result from the interaction between the -C=O groups in the nanoporous graphene and the -CF 2 groups in PVDF, which also explains the important role of GOs in the preparation of the graphene-polymer nanocomposites with superior combined mechanical and electro-mechanical properties.

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Formation of piezoelectricβ-phase crystallites in poly(vinylidene fluoride)-graphene oxide nanocomposites under uniaxial tensions

Cited by 23 publications

References 21 publications

Effective gas separation through graphene oxide containing mixed matrix membranes

Effective gas separation through graphene oxide containing mixed matrix membranes

Piezoelectric Response in Electrospun Poly(vinylidene fluoride) Fibers Containing Fluoro-Doped Graphene Derivatives

Mechanical and electro-mechanical properties of three-dimensional nanoporous graphene-poly(vinylidene fluoride) composites

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