Search

Summary: The current research paper presents an investigation of the piezoelectric performances of five different polyvinylidene fluoride hexafluoropropylene (PHP) systems fabricated by electrospinning. Morphological and structural analyses of neat PHP, PHP/zinc oxide 1% (PHP‐Z), PHP/mesoporous silica 1% (PHP‐M), PHP/ZnO‐mesoporous silica at 1 wt.% (PHP‐MZ1), and PHP/ZnO‐mesoporous silica at 3 wt% (PHP‐MZ3) were carried out systematically by scanning electron microscopy, transmission electron microscope, energy‐dispersive X‐ray spectroscopy (EDX), and X‐ray diffraction (XRD). The microscopic analysis results show the formation of uniform ZnO nanoflakes of approximately 5 nm in diameter, whereas mesoporous silica particles form a uniform spherical structure with a typical diameter of 5 μm. Elemental analysis by EDX spectra confirms the presence of Zn, O, and Si in the prepared nanocomposites. The crystalline β‐phase of PHP in the Fourier transformation infrared spectra rises with the addition of ZnO and mesoporous silica particles to the polymer matrix. Neat polyvinylidene fluoride has the most intense XRD peak in comparison to all other polymer nanocomposites. The fabricated flexible nanogenerator obtained from the 1% ZnO‐mesoporous silica nanocomposite shows an output voltage of 2 V, whereas the nanogenerator prepared using the neat PHP sample exhibits an output voltage of ~120 mV. All of the results indicate that the 1% ZnO‐mesoporous silica PHP nanocomposite is suitable for constructing low‐powered wearable self‐driven electrical devices. [ABSTRACT FROM AUTHOR]

In this work, stable hydrophobic nanocomposites are made from electrospun fibers of polystyrene (PS) containing a hybrid filler combination of (i) hexagonal boron nitride (hBN) and (ii) cobalt oxide (Co3O4) nanomaterials. Good synergistic interaction is observed between the nanomaterials, since the growth of Co3O4 was carried out in presence of white graphene nanosheets. Filler synergy modifies the PS surfaces, by enhancing the filler-polymer interfacial interactions and provides good tensile strength. The hydrophobic films are gamma irradiated to improve crosslinking within the polymer nanocomposites. Since gamma irradiation enhances the surface roughness, its hydrophobicity/oleophilicity increases much and the final nanofibers show good oil-water separation efficiency. The nanofibers act as sponge clothing to skim the oil from a mixture of oil and water. Durability of the fibers in hot water and in presence of ultrasonic waves is also tested and good response is achieved. Contact angle studies are performed to investigate the surface properties and to check the influence of gamma irradiation on the surface wettability. The gamma-irradiated PS nanocomposite fiber shows a contact angle of 152° ± 2° compared to the 140° ± 1° of the neat PS fiber, evidencing the superhydrophobicity. Both the effects of crosslink density enhancement and hybrid filler distribution make the composite fibers stronger in oil absorption application even at higher operation temperatures. The fibers are reported to be robust and durable, in addition. [ABSTRACT FROM AUTHOR]

Nickel ferrite nanoparticles (NiFe 2 O 4) synthesized by chemical co-precipitation method, are added to poly(vinylidene fluoride-co-hexafluoroproplyene) (PVDF-HFP) in specific concentrations (1, 2, and 3 wt%) and the composite nanofibers are fabricated by electrospinning. Structural investigation and morphology of the synthesized NiFe 2 O 4 magnetic nanoparticles reveal its spinel nature. The crystalline behavior in addition to the ferroelectric properties of NiFe 2 O 4 enhance the interfacial interaction with the polymer chains and creates better dipole alignment and phase transformations within the nanocomposite. The nanocomposite with 1 wt% NiFe 2 O 4 shows the maximum dielectric constant of 118 at 1 Hz frequency, which is about 24 times higher than that of the neat polymer. At the typical concentration of 2 wt% NiFe 2 O 4 in PVDF-HFP, the nanocomposite is capable to generate an output voltage of 4 V suggesting the possible use of those flexible and magnetic polymer nanocomposites in designing piezoelectric devices. The structural performance, dielectric properties and the energy harvesting performance of the PVDF-HFP/NiFe 2 O 4 nanocomposites are demonstrated here based on the filler and polymer characteristics. • Electrospun fibers of flexible ferroelectric nanocomposite achieve an output voltage of 4 V. • NiFe 2 O 4 nanoparticles improve the crystallization temperature and the dielectric constant of PVDF-HFP. • Dipole alignment in nanocomposite depends on NiFe 2 O 4 , phase transformation and spinning parameters. [ABSTRACT FROM AUTHOR]