On the origin of the electroactive poly(vinylidene fluoride) β-phase nucleation by ferrite nanoparticles via surface electrostatic interactions

Martins, P.; Costa, Carlos M.; Benelmekki, Maria; Botelho, Gabriela; Lanceros‐Méndez, S.

doi:10.1039/c2ce06654h

Cited by 249 publications

(173 citation statements)

References 36 publications

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“…This result demonstrates that the presence of nanocrystallites of KNN in PVDF promotes strong electrostatic interaction between KNN at nanoscale and the PVDF polymer especially at the interface, leading to the alignment of the PVDF matrix in the extended TTTT conformation and resulting in the β-phase. Similar behavior is observed in the PVDF with various fillers such as BaTiO 3 , MWCNT, TiO 2 , and ferrite-based composites [41,[52][53][54][55]. It is known in the literature that high pressure favors β-phase formation of PVDF [10].…”

Section: Resultssupporting

confidence: 56%

Effect of nano- and micron-sized K0.5Na0.5NbO3 fillers on the dielectric and piezoelectric properties of PVDF composites

2016

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Polymer nanocrystal composites were fabricated by embedding polyvinylidene fluoride (PVDF) with K 0.5 Na 0.5 NbO 3 (KNN) nanocrystallites of different volume fraction using the hot-pressing technique. For comparison, PVDF-KNN microcrystal composites of the same compositions were also fabricated which facilitated the studies of the crystallite size (wide range) effect on the dielectric and piezoelectric properties. The structural, morphological, dielectric, and piezoelectric properties of these nano and micro crystal composites were investigated. The incorporation of KNN fillers in PVDF at both nanometer and micron scales above 10 vol% resulted in the formation of polar β-form of PVDF. The room temperature dielectric constant as high as 3273 at 100 Hz was obtained for the PVDF comprising 40 vol% KNN nanocrystallites due to dipole-dipole interactions (as the presence of β-PVDF is prominent), whereas it was only 236 for the PVDF containing the same amount (40 vol%) of micron-sized crystallites of KNN at the same frequency. Various theoretical models were employed to predict the dielectric constants of the PVDF-KNN nano and micro crystal composites. The PVDF comprising 70 vol% micron-sized crystallites of KNN exhibited a d 33 value of 35 pC/N, while the nanocrystal composites of PVDF-KNN did not exhibit any piezoelectric response perhaps due to the unrelieved internal stress within each grain, besides the fact that they have less domain walls.

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Section: Resultssupporting

confidence: 56%

Effect of nano- and micron-sized K0.5Na0.5NbO3 fillers on the dielectric and piezoelectric properties of PVDF composites

2016

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“…CFO nanoparticle content has no significant impact on the nanofibre average diameter [ Figure 1 (a-d)]. The CFO/PVDF nanofibres show a strong enhancement in the volume fraction of electroactive β phase F β [11,12] when compared to pure PVDF electrospun nanofibers [ Figure 1(e) and (f)], as the interaction between the negatively charged surface of the CFO nanoparticles (whose zeta potential is -22 mV) and the positively charged polymer CH 2 groups promotes nucleation of the polar β phase, as seen in CFO/PVDF films [10]. The increase in β phase volume fraction is also assisted by the low evaporation temperature of the solvent (≤ 60 o C) and the stretching that occurs during jet formation [13].…”

Section: Resultsmentioning

confidence: 99%

Magnetoelectric CoFe₂O₄/polyvinylidene fluoride electrospun nanofibres

et al. 2015

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Magnetoelectric 0-1 composites comprising CoFe2O4 (CFO) nanoparticles in a polyvinylidene fluoride (PVDF) polymer-fibre matrix have been prepared by electrospinning. The average diameter of the electrospun composite fibres is ∼325 nm, independent of the nanoparticle content, and the amount of the crystalline polar β phase is strongly enhanced when compared to pure PVDF polymer fibres. The piezoelectric response of these electroactive nanofibres is modified by an applied magnetic field, thus evidencing the magnetoelectric character of the CFO/PVDF 0-1 composites.

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“…It is to notice that those β-phase contents are compatible with the maximum piezoelectric response of the polymer, as it has been verified in 33 . In this way, the β-phase formation is mainly attributed to the low solvent evaporation temperature (≤ 60 o C), which mainly leads to the crystallization of the polymer in this phase 15,34 . Further, electrostatic interaction of the filler nanoparticles with the highly polar polymer chains certainly reinforce this effect, as it has been verified in samples prepared after melting, that are nucleated in the β-phase, whereas the polymer without fillers remain in the α-phase 15 .…”

Section: Resultsmentioning

confidence: 99%

“…Figure 2) as a function of filler content. The presence of the CFO nanoparticles improves the piezoelectric response of composite spheres due to the electrostatic interactions between particles and polymer 31,34 . Once a 220 mT DC magnetic field was applied with two permanent magnets, at the same time that the piezoelectric response is being measured, an increase in the |d 33 | value is observed in the composite samples but no variation is detected in the pristine polymer samples revealing the ME character of the multiferroic spheres (Figure 2b).…”

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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On the origin of the electroactive poly(vinylidene fluoride) β-phase nucleation by ferrite nanoparticles via surface electrostatic interactions

Cited by 249 publications

References 36 publications

Effect of nano- and micron-sized K0.5Na0.5NbO3 fillers on the dielectric and piezoelectric properties of PVDF composites

Effect of nano- and micron-sized K0.5Na0.5NbO3 fillers on the dielectric and piezoelectric properties of PVDF composites

Magnetoelectric CoFe₂O₄/polyvinylidene fluoride electrospun nanofibres

Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres

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On the origin of the electroactive poly(vinylidene fluoride) β-phase nucleation by ferrite nanoparticles via surface electrostatic interactions

Cited by 249 publications

References 36 publications

Effect of nano- and micron-sized K0.5Na0.5NbO3 fillers on the dielectric and piezoelectric properties of PVDF composites

Effect of nano- and micron-sized K0.5Na0.5NbO3 fillers on the dielectric and piezoelectric properties of PVDF composites

Magnetoelectric CoFe2O4/polyvinylidene fluoride electrospun nanofibres

Development of magnetoelectric CoFe2O4 /poly(vinylidene fluoride) microspheres

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Product

Resources

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Magnetoelectric CoFe₂O₄/polyvinylidene fluoride electrospun nanofibres

Development of magnetoelectric CoFe₂O₄ /poly(vinylidene fluoride) microspheres