α- and γ-PVDF: Crystallization kinetics, microstructural variations and thermal behaviour

Silva, Marco Aurélio Pinto; Sencadas, Vítor; Botelho, Gabriela; Machado, A. V.; Rolo, Anabela G.; Rocha, J. G.; Lanceros-Méndez, S.

doi:10.1016/j.matchemphys.2010.02.067

Cited by 99 publications

(92 citation statements)

References 17 publications

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“…In this initial degradation step the decomposition mechanism is chain-stripping where carbon-hydrogen and carbon-fluorine scission occurs, the presence of both hydrogen and fluorine radicals leading to the formation of hydrogen fluoride 37,39 . The second degradation step occurs between ≈500 and ≈850 o C(iii), and the differences observed in the plots relatively to the pure PVDF spheres sample are to be ascribed to the presence of CFO nanoparticles, as the different phases of PVDF show similar thermal degradation behavior 40 . This second step is a complex degradation process resulting in poly(aromatization).…”

Section: Resultsmentioning

confidence: 99%

Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres

et al. 2015

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Magnetoelectric microspheres based on piezoelectric poly(vinylidene fluoride) (PVDF) and magnetostrictive CoFe 2 O 4 (CFO), a novel morphology for polymer-based ME materials, have been developed by an electrospray process. The CFO nanoparticle content in the (3-7 mm diameter) microspheres reaches values up to 27 wt%, despite their concentration in the starting solution reaching values up to 70 wt%. Additionally, the inclusion of magnetostrictive nanoparticles into the polymer spheres has no relevant effect on the piezoelectric b-phase content (z60%), crystallinity (40%) and the onset degradation temperature (460-465 C) of the polymer matrix. The multiferroic microspheres show a maximum piezoelectric response |d33| z 30 pC N1, leading to a magnetoelectric response of D|d33| z 5 pC N1 obtained when a 220 mT DC magnetic field was applied. It is also shown that the interface between CFO nanoparticles and PVDF (from 0 to 55%) has a strong influence on the ME response of the microspheres. The simplicity and the scalability of the processing method suggest a large application potential of this novel magnetoelectric geometry in areas such as tissue engineering, sensors and actuators. Magnetoelectric microspheres based on piezoelectric poly(vinylidene fluoride) (PVDF) and magnetrostrictive CoFe 2 O 4 (CFO), a novel morphology for polymer-based ME material, have been developed by an electrospray process. The CFO nanoparticles content in the (3 -7 µm diameter) microspheres reaches values up to 27 wt.%, despite their concentration in the starting solution reaching values up to 70 wt.%. Additionally, the inclusion of magnetostrictive nanoparticles into the polymer spheres has no relevant effect on the piezoelectric β-phase content (≈60%), crystallinity (40%) and the onset degradatio n temperature (460º-465ºC) of the polymer matrix. The multiferroic microspeheres show a maximum piezoelectric reponse |d33|≈30 pC.N -1 , leading to a magnetoelectric response of ∆|d33|≈5 pC.N -1 obtained when a 220 mT DC magnetic field was applied. It is also shown that the interface between CFO nanoparticles and PVDF (from 0 to 55%) has a strong influence on the ME response of the microspheres. The simplicity and the scalability of the processing method suggest a large application potential of this novel mag netoelectric geometry in areas such as tissue engineering, sensors and actuators.

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Section: Resultsmentioning

confidence: 99%

Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres

et al. 2015

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“…Spherulitic structure of α-phase is seen on the surface of pure PVDF film. 18 However, is not prominently seen in the composite and rather uniform distribution of bright spots corresponding to the metallic LSMO particles dispersed in the PVDF matrix are seen. The images also confirm voids and porous free structure which is essential for electrical measurements.…”

Section: Resultsmentioning

confidence: 95%

Magnetic, dielectric and magnetodielectric properties of PVDF-La0.7Sr0.3MnO3 polymer nanocomposite film

Thirmal¹,

Nayek²,

Murugavel³

et al. 2013

AIP Advances

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We have investigated the structure, magnetic and dielectric properties of PVDFLa 0.7 Sr 0.3 MnO 3 polymer nanocomposite thick film fabricated by dip coating technique along with the magnetodielectric effect. The structure and dielectric properties show the enhanced β phase in the composite compared to the PVDF film. The coupling between the ferroelectric and magnetic phases in the composite is revealed in the form of dielectric anomaly at the ferromagnetic Curie temperature. We observed 1.9% magnetodielectric effect at 300 K with the possibility of enhanced effect near the transition temperature. In addition, the analysis of the electric modulus indicates that the composite exhibits interfacial related relaxation and it follows Arrhenius Law. Our study suggests that the ac conductivity of the PVDF-La 0.

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“…Thus, the aniline polymers are basically poly(p-phenyleneamine)s, in which the intrinsic oxidation states can vary from that of the fully reduced leucoemeraldine (y = 1), through that of the 50% intrinsically oxidized pernigraniline (y = 0). The polymer can achieve a highly conductive state either through protonation (doping) of the imine nitrogens (=N-) or through the oxidation of the amine nitrogens (-NH-) in its fully reduce leucoemeraldine state [17].…”

Section: Introductionmentioning

confidence: 99%

“…The electroactive properties of this material heavily depend on the phase content, microstructure and crystallinity degree of the material, which in turn depend on the processing conditions [17]. PVDF exists in four different phases.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the microstructure of α-PVDF plays an important role in the α-to β-phase transformation by stretching. This stretching process is the typical way for obtaining the most common electroactive polymorph and deeply influences the properties of the β-phase [17]. Often in the form of films, PVDF is mechanically drawn to orient its molecules and polarized to yield strong piezoelectric behavior.…”

Section: Introductionmentioning

confidence: 99%

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Study of the effect of synthesis parameters in the electrical conductivity of the composite poly (vinylidene fluoride) / polyaniline

et al. 2017

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Estudo do efeito dos parâmetros de síntese na condutividade elétrica do compósito fluoreto de polivinilideno / polianilinaStudy of the effect of synthesis parameters in the electrical conductivity of the composite poly (vinylidene fluoride) / polyaniline ABSTRACTThe electroactive polymers have been the subject of many studies in the last decade, mainly because its unique properties. They are used in composite structures, which allow its application in many fields, as for example, sensors and artificial muscles. The electrical properties of these composites are influenced by the doping state of the electroactive polymer, which is controlled during its synthesis process. Therefore, this work aimed to evaluate how the synthesis parameters influence the electrical conductivity of the composite PANI/PVDF.The synthesis parameters evaluated were the concentrations of monomer, initiator and dopant, and the synthesis time. PANI was obtained by chemical polymerization in a solution containing PVDF and the solvent DMF. To evaluate possible changes in the chemical structure of the composite, the samples were submitted to FT-IR and XRD analysis. It was possible to conclude that the parameters relative to the production of PANI directly influence in the electrical conductivity of the composite. So, the sample produced with major quantities of monomer, initiator and dopant were statistically significant to increase the electrical property of the composite.

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α- and γ-PVDF: Crystallization kinetics, microstructural variations and thermal behaviour

Cited by 99 publications

References 17 publications

Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres

Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres

Magnetic, dielectric and magnetodielectric properties of PVDF-La0.7Sr0.3MnO3 polymer nanocomposite film

Study of the effect of synthesis parameters in the electrical conductivity of the composite poly (vinylidene fluoride) / polyaniline

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α- and γ-PVDF: Crystallization kinetics, microstructural variations and thermal behaviour

Cited by 99 publications

References 17 publications

Development of magnetoelectric CoFe2O4 /poly(vinylidene fluoride) microspheres

Development of magnetoelectric CoFe2O4 /poly(vinylidene fluoride) microspheres

Magnetic, dielectric and magnetodielectric properties of PVDF-La0.7Sr0.3MnO3 polymer nanocomposite film

Study of the effect of synthesis parameters in the electrical conductivity of the composite poly (vinylidene fluoride) / polyaniline

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Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres

Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres