Smart and robust electrospun fabrics of piezoelectric polymer nanocomposite for self-powering electronic textiles

The present work designs a piezoelectric nanogenerator (PENG) based on the electrospun nanofibers of the piezoelectric polymer, polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), by uniformly drawing the spun membranes containing cellulose nanocrystals (CNC, 2 wt%) and the Fe-doped nano ZnO (2 wt%). The hybrid nanocomposite fibers were made in double layers, with CNC/PVDF-HFP composite on one side and the Fe-doped ZnO/PVDF-HFP on the other side. This ferroelectric polymer composite exhibited maximum peak-to-peak output voltage of 12 V with a current density, 1.9 ?Acm?2, which are respectively higher by 60 and 2.3 times compared to the neat polymer fibers. The PENG is tested for its energy harvesting ability by exposing it to different environments such as ultrasound vibrations and human body movements during hand tapping, elbow movements and by attaching with the textile fabrics. While the finger tapping generated peak-to-peak output voltage of 6.5 V, elbow movements resulted in 5.5 V generation. In all sorts of movements, the nanogenerator shows good output performance indicating its compatibility with textile materials. The mechanical properties, breakdown strength and dielectric properties of the material are also in accordance with its possible applications in wearable electronic textiles. - 2019 The AuthorsThis publication is made possible by NPRP grant 6-282-2-119 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Designing carbon nanotube-based oil absorbing membranes from gamma irradiated and electrospun polystyrene nanocomposites

Carbon-based materials are outstanding candidates for oil spill clean-ups due to their superhydrophobicity, high surface area, chemical inertness, low density, recyclability, and selectivity. The current work deals with the fabrication of membrane oil absorbents based on carbon nanotube (CNT) reinforced polystyrene (PS) nanocomposites by electrospinning technique. The spun membranes are also irradiated with the gamma radiation to induce enough crosslinks and thus good polymer-filler interactions. The structural, morphological, and surface properties in addition to the oil/water separation efficiency were investigated by varying the concentration of CNT and the dose of γ-irradiation. Fabricated nanofiber membranes show superior hydrophobicity and selective oil absorption at 0.5 wt.% of CNT concentration. The best mechanical properties are also obtained at this particular concentration and at 15 KGy optimum γ-irradiation dosage. The gamma irradiated PS/0.5 wt.% CNT membrane also exhibits good antibacterial effects against the bacteria, Escherichia coli, in the form of bacterial inhibition rings around the membranes. The present study thus shows the environmental applicability of the fabricated PS/CNT membranes in treating oil-contaminated water

Effect of anions on the structural, morphological and dielectric properties of hydrothermally synthesized hydroxyapatite nanoparticles

Synthetic nano hydroxyapatites (HA) have been considered as potential biomaterials for bone tissue engineering applications because of its excellent biological properties. The present work deals with the synthesis of HA nanoparticles from different anion source materials via autoclave assisted hydrothermal method. All the prepared HA nanoparticles were characterized by X-ray diffraction (XRD), Fourier transformation infrared spectra, field emission scanning electron microscopy, energy dispersive spectra and high resolution transmission electron microscopy. The XRD patterns reveal the pure and hexagonal phase structure with smaller crystallite size for HA obtained from various calcium salt precursors. HA particles prepared from nitrate precursors show spherical morphology with 32 nm grain size whereas those derived from the acetate, chloride and egg shell precursors respectively show needle-like, irregular and oval morphology. The effect of different anions on the dielectric properties and alternating conductivity of HA is investigated, as a polarized surface can trigger biological reactions. For the particles obtained from nitrate, acetate, chloride and egg shell precursors respectively give dielectric constant (εʹ) values of 9.96, 13.22, 9.92 and 10.86 at 5 MHz. The εʹ and dielectric loss (εʹʹ) values for the HA nanoparticles decrease with increase in the applied frequency as well. The alternating current conductivity values confirm that the as-synthesized HA samples exhibit insulating behavior. In short this article provides the various applicability of HA particles in optoelectronics and drug delivery.Open access funding provided by the Qatar National LibraryScopu

Enhanced corrosion protection of Epoxy/ZnO-NiO nanocomposite coatings on steel

ZnO-NiO nanocomposite with epoxy coating on mild steel has been fabricated by the sol–gel assisted method. The synthesized sample was used to study corrosion protection. The analysis was performed by electrochemical impedance spectroscopy in 3.5% NaCl solution. The structural and morphological characterization of the metal oxide nanocomposite was carried out using XRD and SEM with Energy Dispersive Absorption X-ray (EDAX) analysis. XRD reveals the ZnO-NiO (hexagonal and cubic) structure with an average ZnO-NiO crystallite size of 26 nm. SEM/EDAX analysis of the ZnO-NiO nanocomposite confirms that the chemical composition of the samples consists of: Zn (8.96 ± 0.11 wt.%), Ni (10.53 ± 0.19 wt.%) and O (80.51 ± 3.12 wt.%). Electrochemical Impedance Spectroscopy (EIS) authenticated that the corrosion resistance has improved for the nanocomposites of ZnO-NiO coated along with epoxy on steel in comparison to that of the pure epoxy-coated steelThis research was funded by the Undergraduate Research Experience Program project no. UREP24-133-2-036 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. This work was supported by the UREP grant # UREP24-133-2-036 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The authors would like to thank the Central laboratory Unit (CLU), Qatar University, 2713, Doha, Qatar, for SEM with EDAX analysis facility.Scopu

Investigation on the effect of γ-irradiation on the dielectric and piezoelectric properties of stretchable PVDF/Fe–ZnO nanocomposites for self-powering devices

Stretchable films of PVDF nanocomposites containing iron doped ZnO (Fe-ZnO) nanoflowers are fabricated following simple solution mixing and ?-irradiation treatment. An increase in ?-phase crystallinity is noticed for the PVDF/Fe-ZnO nanocomposite when compared to PVDF/ZnO at the same filler concentration. Specifically, at 1 wt%, the relative crystallinity of the composite containing Fe-ZnO calculated from FTIR is 48.1%, while for ZnO, it is 40.9%. A dielectric constant of 96 is reached for PVDF/Fe-ZnO at 2 wt%, in addition to a peak to peak output piezoelectric voltage of 2.4 V. This is several times higher than that observed for PVDF/ZnO nanocomposites and those fabricated without ?-irradiation (1.1 V). Piezoelectric voltage generation is also observed during the stretching, bending and rolling vibrational movements of the sample, indicating its possible use in flexible electronic devices. The observed superior performance of the PVDF/Fe-ZnO system is attributed to the influence of the star like morphology and dispersion of Fe-ZnO, and the enhanced filler-polymer interaction and crosslink formation by the ?-irradiation process. It is demonstrated that such a system can be applicable in manufacturing piezoelectric nanogenerators for various industrial applications including robotic parts, biomedical devices etc. 2018 The Royal Society of Chemistry.This publication is made possible by NPRP grant 6-282-2-119 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors

Effect of cerium doping on the optical and photocatalytic properties of ZnO nanoflowers

Photocatalytic performances of the synthesized cerium doped (Ce-doped) ZnO nanoflowers are reported in this work. A microwave-assisted sol–gel method is adopted for the synthesis of the nanomaterial and its structural and morphological features are characterized. While doping, the Ce3+ ions occupy the sites of Zn2+ ions in the hexagonal ZnO lattice, which is investigated by means of X-ray diffraction studies and energy dispersive X-ray analysis. At higher Ce3+ concentrations, ultraviolet (UV) light absorption is quite high as evidenced by the UV–Vis absorption spectra. The photoluminescence study demonstrates higher oxygen vacancy and zinc interstitials for the Ce-doped ZnO compared to the undoped ZnO. Ce-doping improves the electrical properties of the sample as well. Finally, it is established that the Ce-doped ZnO nanoflower is highly efficient in UV degrading the methylene blue organic dye.Scopu

Toward High Power Generating Piezoelectric Nanofibers: Influence of Particle Size and Surface Electrostatic Interaction of Ce-Fe 2 O 3 and Ce-Co 3 O 4 on PVDF

Development of flexible piezoelectric nanogenerator (PENG) is a real challenge for the next-generation energy-harvesting applications. In this paper, we report highly flexible PENGs based on poly(vinylidene fluoride) (PVDF)/2 wt % Ce-Fe 2 O 3 and PVDF/2 wt % Ce-Co 3 O 4 nanocomposite fibers. The incorporation of magnetic Ce-Fe 2 O 3 and Ce-Co 3 O 4 greatly affects the structural properties of PVDF nanofibers, especially the polymeric ? and ? phases. In addition, the new composites enhanced the interfacial compatibility through electrostatic filler-polymer interactions. Both PVDF/Ce-Fe 2 O 3 and PVDF/Ce-Co 3 O 4 nanofibers-based PENGs, respectively, produce peak-to-peak output voltages of 20 and 15 V, respectively, with the corresponding output currents of 0.010 and 0.005 ?A/cm 2 under the force of 2.5 N. Enhanced output performance of the flexible nanogenerator is correlated with the electroactive polar phases generated within the PVDF, in the presence of the nanomaterials. The designed nanogenerators respond to human wrist movements with the highest output voltage of 0.15 V, for the PVDF/Ce-Fe 2 O 3 when subjected to hand movements. The overall piezoelectric power generation is correlated with the nanoparticle size and the existing filler-polymer and ion-dipole interactions.This publication was made possible by NPRP grant 6-282-2-119 from the Qatar National Research Fund (a member of Qatar Foundation)Scopu

Flexible tri-layer piezoelectric nanogenerator based on PVDF-HFP/Ni-doped ZnO nanocomposites

In this work, we report Ni doped ZnO/poly(vinylidene fluoride-hexafluoropropylene) [PVDF-HFP] nanocomposites prepared by sandwiching and their structural, morphological, thermal, electrical and piezoelectric properties. The X-ray diffraction analysis and Fourier transform infrared spectral (FTIR) studies of the nanocomposite films confirm the enhanced ?-phase crystallization in the PVDF-HFP matrix due to the Ni-doped ZnO nanoparticles. Microscopic images of the prepared samples substantiate homogeneous dispersion of Ni-doped ZnO nanoparticles in the polymer matrix resulting in higher ?-phase nucleation. In addition, the nanocomposite shows a high dielectric constant and low dielectric loss, making it suitable for energy storage. The piezoelectric property increases with the filler concentration and a maximum generated output voltage of 1.2 V is achieved at 0.5 wt% Ni-doped ZnO.Scopu

Nanoflower-like Yttrium-doped ZnO Photocatalyst for the Degradation of Methylene Blue Dye

Pure ZnO and Yttrium-doped (Y-doped) ZnO at various mol% with flower-like nanostructures are synthesized by a microwave-assisted sol�gel method, followed by investigating the morphologies, crystal structures, optical properties and photocatalytic performances. While the phase formations are detected by X-ray diffraction technique, both scanning and transmission electron microscopy images clearly depict the flower-like morphology of ZnO and Y-doped ZnO samples. Formation of flower petals is from the nanoparticles that grew and connected by orientation attachment process. The flower-like architecture is addressed in terms of an Ostwald ripening mechanism. The UV-Vis absorption studies show enhanced absorption for the Y-doped ZnO, whereas the photoluminescence spectra confirm the significance of sample defects in the photocatalytic degradation of organic pollutants. Effects of various experimental parameters such as the amount of photocatalysts, dye concentration and dopant concentration on the dye degradation are also optimized. - 2017 The American Society of PhotobiologyScopu