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Polymer nanocomposite was prepared using poly(vinylidene fluoride-trifluoroethylene) and zinc oxide (ZnO) nanopowder, which are ferroelectric in nature. Nanocomposite was prepared in various concentrations(0.2, 0.4, 0.8, and 1wt. %) using probe ultra-sonication, followed by spin coating and annealing at 120 °C for 2 h to improve the formation of β-phase. Metal-ferroelectricmetal capacitor was fabricated using this optimized thin film as a ferroelectric layer. Device level optimization was carried out by polarization-electric field (P-E) hysteresis studies of this film, which shows polarization enhancement of composite. Various characterization techniques like atomic force microscopy, Fourier transform infra-red spectroscopy (FT-IR), Differential scanning calorimetry, and X-ray diffraction were used to study the β-phase formation of nancomposite. The capacitance-voltage (C-V) and current-voltage (I-V) characteristics were studied through varying frequency and temperature. C-V measurements show an increase of 79% in the capacitance of polymer nanocomposite, which can be used for the fabrication of ferroelectric devices. [ABSTRACT FROM AUTHOR]

Nanocomposites of polyvinylidene fluoride/polymethyl methacrylate (PVDF/PMMA) blend and mechanically activated barium titanate (BaTiO3) particles were prepared by melt mixing. Modification of filler by means of mechanical activation has a profound effect on the crystallization of PVDF in the blend matrix. Raman analysis showed that the modified BaTiO3 particles, due to higher specific surfaces, induce, predominantly, the crystallization of the electrically active β-phase of PVDF, while the initial micron size particles induce the formation of the most common but non-polar a-crystal form. The introduction of activated particles reduces the overall crystallinity but slightly affects the crystallization and melting temperatures of the matrix. Dielectric spectroscopy revealed that at fixed filler content the dielectric constant of the blend increases with decreasing of the particle size (increasing of the activation time). A similar trend was observed for the storage moduli in dynamic mechanical analysis; the stiffness of the composite was higher when mechanically activated particles were used. [ABSTRACT FROM AUTHOR]

Various methods have been used to study the thermal conductivity of nanocomposites which are playing increasing roles in energy conversion and thermal management. However, when the size of particle inclusions is on the order of several nanometers, the existing macro- and meso-scale analytical methods cannot be used to predict the thermal conductivity of nanocomposites due to the existence of both phonon wave interference and particle scattering effects. In this study, equilibrium molecular dynamics (EMD) is explored to study the thermal conductivity of Si/Ge nanocomposites. We found that EMD can be used to study the thermal conductivity of nanocomposites when multiple nanoparticles are included to avoid the artificial effect of simulation domain sizes. We then calculated the thermal conductivity of Si/Ge nanocomposites with different volumetric ratio and particle size at 300 K. The result shows that the thermal conductivity of Si/Ge nanocomposites first decreases and then increases with decreasing particle size at fixed volumetric ratio. The decreasing thermal conductivity is due to the increased phonon scattering at high surface to volumetric ratio. When the particle size is further reduced, the thermal conductivity recovers due to the phonon wave interference effect. The effect of particle shape on the thermal conductivity of Si/Ge nanocomposites is also studied. [ABSTRACT FROM AUTHOR]

In this paper a novel multi-functional composite with high electrical conductivity and excellent magnetic field sensitivity was fabricated by embedding carbon nanotubes (CNTs) and carbonyl iron powders (CIPs) into shear-stiffening gel (STG). Oscillatory shear test demonstrated its excellent rheological properties. When the mass fractions of CNTs and CIPs were 1 wt% and 50 wt%, the increase in storage modulus (G′) reached 585% under 100 Hz oscillatory shear and 428% under 1.2 T magnetic flux density with respect to its initial state. The resistivity of this CNT-CIP-STG composite achieved 25 Ω m and showed strong dependence on the magnetic field. When the external magnetic flux density was 873 mT, the normalized electrical resistance response reached up to − 40.5%. Linearly increasing and step magnetic field was employed to study the electrical and mechanical behaviors of this CNT-CIP-STG composite. The instantaneous response and time effect were discussed. Interestingly, oscillatory shear showed limited influence on the electrical conductivity but notable enhancement on the sensitivity to magnetic field. A mechanic-electric coupling mechanism was proposed to illustrate enhancement of shear thickening effect and sensibility to magnetic field. [ABSTRACT FROM AUTHOR]

Abstract In this work, the rheological and electrical behavior of carbon black (CB) filled poly(methyl methacrylate) (PMMA) nanocomposites in the molten state as a function of CB concentration were investigated by simultaneous electrical and rheological measurements. Shear deformations applied during a stress amplitude sweep caused both changes in the linear viscoelastic behavior and electrical conductivity. The storage modulus increased with measuring time for all PMMA nanocomposites. However, the changes in the time-dependent behavior of storage modulus decreased above the percolated CB concentrations for all investigated nanocomposites, which was in good agreement with the changes in the time-dependent electrical conductivity. The different behaviors can be explained by the agglomeration of CB particles and the decrease of averaged force on a single CB particle. Highlights • Shear deformation applied during stress amplitude sweep caused both changes in the linear viscoelastic and conductivity • Time-dependent behavior of storage modulus was agreed with the conductivity at above the percolated CB content. • Different behaviors were attributed to the CB agglomeration and the decrease of averaged force on a single CB particle. [ABSTRACT FROM AUTHOR]

Flexible nylon 11/CaCu 3 Ti 4 O 12 (CCTO) nanocomposite films (thickness ∼100 μm) with varying CCTO nanoceramics (0 to 30 wt%) were fabricated by solution casting method followed by vacuum drying. The nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy, and impedance analyzer to study their structural and dielectric properties. XRD analysis revealed the presence of γ-phase of nylon 11 both in as-cast film as well as in the composites. SEM micrographs indicated that the CCTO nanocrystals were distributed evenly throughout the nanocomposite films with less agglomeration. The room temperature dielectric permittivity was 168 at 50 Hz when the CCTO content increased to 30 wt% in the polymer and this was increased to 1007 at 423 K. Frequency independent dielectric behavior was observed for the frequency range of 100 kHz–10 MHz. Temperature coefficient of permittivity showed that the permittivity of the nanocomposites is highly temperature dependent. [ABSTRACT FROM AUTHOR]

The dielectric material employed in this effort is a proprietary nanocomposite material, MU100. The material was initially developed to shrink high frequency high voltage dielectric loaded antennas; however, due to its unique material characteristics, the nanocomposite has shown promise in development of high voltage capacitors. Previous work has shown small-scale samples of the high permittivity nanocomposite material to have an average dielectric strength of 220 kV/cm with peak breakdown fields in excess of 328 kV/cm. When scaling up to realize application specific voltages, failure modes become more pronounced due to volume effects of the nanocomposite and field enhancement factors at the electrode dielectric interfaces. This work describes how the material was increased in volume from small samples up to compact capacitor prototypes capable of repeatable performance at 250 kV to in excess of 500 kV with lifetimes greater than 104 shots. [ABSTRACT FROM AUTHOR]

This work is based on the preparation of graphene‐reinforced elastomeric nanocomposites and an investigation on their electro‐mechanical properties with a special emphasize to electromagnetic interference (EMI) shielding. Polychloroprene rubber (CR) and commercial grade graphene‐based nanocomposites (GnPs) were prepared by using melt mixing and dual mixing (solution followed by melt) technique to study an insight into the dispersion and its effect on various properties namely, mechanical, thermal, conductivity, and EMI shielding, and so on. Dual mixing technique offers better dispersion of graphene platelets compared with melt mixing technique. Therefore, higher filler‐filled nanocomposites were prepared only by using dual mixing technique. A 0.5 wt% GnP containing batches showed 23% improvement in mechanical property in dual mixing technique compared with the 6% in melt mixing technique. Apart from that, it has been observed that upto 5 wt% GnP containing batches the mechanical property was improved using dual mixing technique whereas the same is observed upto 3 wt% GnP containing batches in case of melt mixing technique. 10 wt% GnP‐based nanocomposites prepared by using dual mixing technique shows 23 dB EMI shielding for 2‐mm thick sheet compound. Maximum 26 dB EMI shielding was observed at 15 wt% GnP containing nanocomposites. POLYM. COMPOS., 40:E1871–E1883, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Highlights • The g-C 3 N 4 /CNHM hybrids with various weight ratios were prepared. • The g-C 3 N 4 /CNHM-2% hybrid exhibited the optimal photocatalytic performance. • Efficient optical nonlinearity was observed for g-C 3 N 4 /CNHM-2%. • The enhanced activity was attributed to the efficient charge transfer effect. Abstract In this study, a series of carbon nitride nano-homojunction (CNHM) decorated carbon nitride (g-C 3 N 4) nanocomposites (g-C 3 N 4 /CNHM) was synthesized by the facile solvothermal method to maximize the photocatalytic and nonlinear optical performances. The structure, optical and electrical properties of the g-C 3 N 4 /CNHM nanocomposites were investigated by various characterization techniques, including Fourier-transform infrared, X-ray photoelectron spectroscopy, X-ray diffraction patterns, Scanning electron microscopy, UV–Vis diffuse reflection spectra and Brunauer-Emmett-Teller method. The photocatalysis and nonlinear optical performance of the g-C 3 N 4 /CNHM nanocomposites are shown to be dependent on the CNHM loadings. The highest photocatalytic activity and obvious nonlinear optical performance were observed for g-C 3 N 4 /CNHM-2%. A rational mechanism for degrading pollutants and observed nonlinear property was proposed, which could be ascribed to the efficient interfacial charge transfer between g-C 3 N 4 and CNHM. The efficient charge separation efficiency was confirmed by the photoluminescence spectroscopy, electrochemical impedance spectroscopy, and photocurrent spectroscopy studies. These results indicate that the multifunctional hybrid materials with tunable optoelectronic performances can be obtained by adjusting the content of CNHM in g-C 3 N 4 /CNHM nanocomposites. [ABSTRACT FROM AUTHOR]

Wearable power sources should be stretchable to provide continuous electricity to devices. In spite of significant progress in the field of wearable electronics, the development of stretchable power sources is still challenging. In this study, we developed a high-performance stretchable thermoelectric generator using multi-dimensional nanocomposites. The thermoelectric power of the metal dichalcogenide (TMD) nanosheet-based active film was significantly enhanced by adding highly conducting single wall carbon nanotubes (one-dimensional material) bridging the multi-stacked TMD nanosheets, which improved the electrical conductivity and morphological stability of the active film, thus increasing its thermoelectric power factor (47 μW/K2 m). The wrinkles on the nanocomposite film rendered it geometrically stretchable. The wrinkled nanocomposite showed significantly improved thermoelectric properties and excellent strain resistance because of the slipping of the TMD nanosheets as a lubricant to release the strain applied to the wrinkles during stretching. [ABSTRACT FROM AUTHOR]

Abstract The present study reports the electrical characteristics of a low voltage ZnO/Polypyrrole nanocomposite varistor which was fabricated as a thin disk based on zinc oxide with different weight percentages of polypyrrole as additive using a cold pressing method. Current-voltage characteristics and nonlinear coefficients of the ZnO/Polypyrrole nanocomposite thin disks were studied in direct current mode. Results showed good varistor behavior of prepared ZnO/Polypyrrole nanocomposite. According to the results, ZnO/Polypyrrole nanocomposite thin disk varistors can be utilized to preserve circuits from 35 V up to 350 V over voltages. I-V characteristics of nanocomposite samples showed that by increasing zinc oxide content from 98.52% to 99.01%, the breakdown voltage of ZnO/Polypyrrole nanocomposite varistor increased whereas its nonlinear coefficient decreased. However, more increase in ZnO content of nanocomposite caused to the reduction of its breakdown voltage and increase of nonlinear coefficient. The results obtained from SEM micrographs indicated that by increasing ZnO content, both the grain numbers and their morphologies are changed which is caused the different effects in the grain boundaries, I-V characteristics, and varistor properties of nanocomposites. As a very important result, in this experimental work, an ideal varistor with sufficient low breakdown voltage and acceptable high nonlinear coefficient was obtained. Highlights • Chemical absorption technique used for synthesizing ZnO/PPy nanocomposites. • The ZnO/PPy nanocomposite disks were prepared using cold pressing method. • The sample with 99.26% ZnO has lower breakdown and higher nonlinear coefficient. [ABSTRACT FROM AUTHOR]

This paper presents fabrication methods for some Multi Walled Carbon Nano Tube (MWCNT)/epoxy composites. These nanocomposite are characterized with respect to temperature and strain. The effect of parameters such as sonication time, percolation threshold, film thickness, use of substrate and formation of electric contact have been observed. These nanocomposites are fabricated: (i) with mould without substrate, (ii) without mould on poly ethylene terephthalate substrate, (iii) without mould without substrate and (iv) without mould without substrate with embedded electrode wire. Field Emission Scanning Electron Microscope of these samples is done to measure the dispersion and agglomerates formation of CNT bundles into polymer matrices. Piezoresistive characterization of these samples with respect to temperature and strain is performed. This paper gives a novel strategy for fabricating a highly sensitive MWCNT/epoxy strain sensor with excellent repeatability. [ABSTRACT FROM AUTHOR]

Graphene has ultra-high electrical and thermal conductivity, which makes graphene as the most encouraging fillers for thermally conductive composites. Graphene and/or carbon black filled conductive polymer composite (CPC) films used as heating element are smarter than the traditional heating elements due to less environmental pollution, ease of application on many surfaces and possess the merits of lightweight. In this study, we investigated mainly the production, characterization and industrial application of graphene/carbon black reinforced styrene acrylic copolymer emulsion matrix composite films deposited on polyvinyl chloride for flexible heating element. After that, the films were dried at room temperature for 24 h in air. Structural and surface properties of the CPC films were characterized by X-ray diffraction and scanning electron microscopy. Temperature, time and voltage relation of the produced composite films were investigated. Heating and electrical properties of the CPC films were determined by using a thermal camera and 4-point probe measurement system, respectively. The electrical resistivity of the CPC films decreases from ~ 108 to 101 Ω cm with increasing the filler content or using a combination of two fillers. Graphene and carbon black filled conductive polymer composites to be considered as candidates for flexible heating element applications exhibited good electrical and heating properties thanks to synergistic effect of fillers. [ABSTRACT FROM AUTHOR]

A new luminescent europium(III) bis-β-diketonate complex, Eu 2 (PBT) 3 (NO 3 ) 3 (PBT = 1,1-(pyridine-2,6-diyl)bis(4,4,4-trifluoro-1,3-dione), was incorporated into the poly(methylmethacrylate) (PMMA) matrix and formed nanofibers via electrospinning technology. The different characterization techniques were adopted to reveal the effect of Eu 2 (PBT) 3 (NO 3 ) 3 on the spatial structure and optical properties of the nano-composite fibers obtained. The doping enhances the thermal stability and filament-forming properties for a series of PMMA-supported composite nanofibers Eu/PMMA, and in particular, the doping concentrations of 11 wt% also showed more efficient luminescence properties. Furthermore, the Judd-Ofelt theory was applied in this study to explain the effect of the distribution of Eu 2 (PBT) 3 (NO 3 ) 3 and the mutual effect of the Eu 2 (PBT) 3 (NO 3 ) 3 coordination compound and surrounding fractions of PMMA. [ABSTRACT FROM AUTHOR]

Magnetite-carbon nanocomposite was grown in situ on nickel foam by a novel auto-combustion method, and it was investigated for application as a pseudocapacitor electrode. Scanning electron microscopy (SEM) images of the magnetite-carbon (Fe3O4-C/Ni) show a sphere-like morphology with a diameter of 50 nm, and the amount of carbon in the nanocomposite was calculated 12.6% based on the thermogravimetric analysis (TGA). Infrared analysis indicates an in situ coating of the Fe3O4 nanospheres by carbon-oxygen moieties. The electrochemical behavior of the nanocomposite was studied in a wide potential window of 0 to − 1.2 V in 3 M KOH solution. The effect of a potential scan rate on the voltammetric currents shows a capacitive-dominant charge storage mechanism due probably to abundant electroactive sites on the electrode surface. A high specific capacitance of 300 F g−1 at 1 A g−1 in a wide potential window from 0 to − 1.2 V was achieved. The cycling stability studies were carried out in two different potential windows over 1000 CV cycles, and the nanocomposite showed a capacitance retention of 73% over 1 V. The pseudocapacitive performance observed here is superior to most of the magnetite-based pseudocapacitors reported to date. [ABSTRACT FROM AUTHOR]

In this paper, free vibration analysis of sandwich composite micro-beam (SCMB) subjected to multi physical fields is investigated using the sinusoidal shear deformation beam theory and modified strain gradient theory (MSGT). SCMB is made of five smart layers including a piezomagnetic core, two piezoelectric layers and nanocomposite facesheets which is rested on Winkler-Pasternak substrate. Due to magnetic and electric properties of SCMB, it is exposed to multi physical fields. The size-dependent governing equations of motion are derived using Hamilton’s principle and solved in a Navier-type sense. Finally, the effects of various parameters such as length to thickness ratio, volume fraction of carbon nanotubes, magneto-electrical loadings and foundation parameters on dimensionless frequency of SCMB are studied. The results of present work can be used to optimum design and control of micro-magneto/electro-mechanical devices. [ABSTRACT FROM AUTHOR]

The radiation-induced conductivity of a nanocomposite with the inclusion of spherical nanoparticles as a function of intensity and time of action of gamma-radiation and the concentration and size of inclusions has been studied using the Rose-Fowler-Weisberg model. The energy spectrum of localized states associated with the nanoparticle inclusion has been determined. The numerical experiments have been made for polymethyl methacrylate (PMMA) nanocomposites with inclusion of CdS and α-Al2O3 nanoparticles as well as SrO nanoparticles. [ABSTRACT FROM AUTHOR]

Nanocomposites composed of chlorinated ethylene propylene diene monomer rubber (Cl‐EPDM) with various contents of hydroxyapatite nanoparticles (HA) were prepared in an open two‐roll mixing mill. The effect of nanoparticle concentration on structural, morphological, thermal, and electrical properties were examined by different characterization technique such as Fourier transform infrared spectroscopy (FTIR), UV, X‐ray diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), thermogravimetric analysis (TGA), and impedance analyzer. The shift in the IR and UV absorption frequencies of nanohybrid relative to that of chlorinated EPDM indicated the successful encapsulation of crystalline hydroxyapatite particles in the modified elastomer chain. The X‐ray diffraction pattern of the fabricated composite revealed the more ordered arrangement of nanoparticles within the elastomer chains and the amorphous nature of polymer decreases with raise in filler loading. The examination of nanocomposite morphology by SEM showed that the inorganic particles were well dispersed in the organic phases. TGA analysis showed the enhanced thermal stability of the composites with increase in the loading of nanoparticles. Shift in the glass transition temperature to a higher value in DSC thermograms of new hybrid indicated the increased orderness of the Cl‐EPDM/HA nanocomposite. The AC electrical conductivity was influenced significantly by the frequency of applied field and the concentration of nanofiller. Dielectric properties strongly distort at lower frequencies but became independent as frequency increased above 103 Hz. POLYM. COMPOS., 39:2093–2100, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

TiO2-ZnO nanocomposites with a constant Ti:Zn molar ratio of 1:0.1 were prepared via sol-gel process followed by calcination at 300, 400, 500, 600, and 700 °C. The structural and compositional characterizations of these nanocomposites were performed through XRD, FTIR, SEM, and EDAX. Bandgap was measured using DRS. Photocatalytic performance of the nanocomposites was evaluated by decolorization of methyl orange dye under UV and visible irradiation with and without aeration. The results showed that increase in calcination temperature resulted in nanocomposites with well-defined morphology. Although the particle size increased with increase in calcination temperature, the crystallinity of the particles also increased, resulting in enhanced photocatalytic activity. A temperature-dependent anatase-to-rutile phase transformation was observed in TiO2-ZnO nanocomposite beyond 600 °C. The calcination temperature influenced both dye adsorption on the nanocomposites and also dye decolorization by photocatalysis. Even when present at low molar concentration, ZnO in the nanocomposite caused sufficient decrease in bandgap (2.6 eV) at temperatures as low as 400 °C, such that visible irradiation could cause dye decolorization. However, the best decolorization performance was observed in the presence of the nanocomposite calcined at 600 °C. Aerated systems showed better performance in all cases. Desorption of the dye remaining adsorbed on the nanocomposite at the end of the photocatalytic reaction, confirmed that adsorption accounted for only 6.6 and 3% of dye removal in the nanocomposites calcined at 600 °C with UV and visible irradiation, respectively. However, in other systems, ignoring adsorption may cause significant overestimation in photocatalytic loss of dye from the system. [ABSTRACT FROM AUTHOR]

The electromagnetic interference (EMI) shielding effectiveness and the intrinsic electrical properties of polymeric material filled with two different nanostructured fillers were investigated. The polymeric material being polyvinylidene fluoride (PVDF) and nickel oxide (NiO) and barium titanate (BaTiO 3 ) were used as nanofillers. The PVDF/NiO/BaTiO 3 nanocomposite films were prepared with the variable concentration of nanofillers using solvent casting method. The structural and morphological analysis of PVDF/NiO/BaTiO 3 nanocomposite films was carried out using Fourier transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM). To understand the EMI shielding effectiveness, the absorption was studied in the Ku-band frequency range (8 Hz–12 Hz). The FTIR analysis shows the interaction between the phases at varying concentrations of nanofillers and the XRD analysis shows characteristic peaks of all the constituents of PVDF/NiO/BaTiO 3 nanocomposites. SEM micrographs of PVDF/NiO/BaTiO 3 nanocomposite film reveal homogeneous dispersion of both NiO and BatiO 3 in the PVDF matrix. The impact of variable concentration of nanofillers on the overall shielding effectiveness (SE) was also investigated with the shielding effectiveness of −11.5 dB. [ABSTRACT FROM AUTHOR]

Applying a nanocomposite to increase the conductivity of an electrode can facilitate electrochemical analysis. In this regard, multi-walled carbon nanotubes (MWCNTs) evenly dispersed in hydrophilic solution can play an important role in electrochemical bio-sensing due to their unique properties, such as their high electrical conductivity and ability to conjugate with hydrophilic enzymes. Herein, we report the simple ultrasonic synthesis of a highly dispersible, enzyme-binding nanocomposite, poly(acrylamide)- co -poly(vinyl imidazole) (7:1 mol ratio)-MWCNTs (PAA-PVI@MWCNTs). This material, having a zeta potential of 36.6 ± 0.53 mV, was applied as a film to an electrode surface and stably bound with glucose oxidase to transfer an electron between the enzyme and electrode in the presence of glucose. The PAA-PVI@MWCNTs composite, which was readily dispersed in deionized water, can be used as a biocompatible material for applications such as bio-sensing, point-of-care testing (POCT), and other health care functions. [ABSTRACT FROM AUTHOR]

The lead lanthanum zirconate titanate (PLZT) nanoscale particles with a cubic crystal cell and the favorable surface activity obtaining from sol-gel method are adopted as the filter. And a ferroelectric poly (vinylidene fluoride- co - trifluoroethylene) (P(VDF- co -TrFE)) copolymer synthesizing by an atom transfer radical polymerization (ATRP) process from commercial poly (vinylidene fluoride- co - chlorotrifluorethylene) (P(VDF- co -CTFE)) is selected as the polymer matrix to form the PLZT/P(VDF- co -TrFE) 0–3 nanocomposites. By expressing the influence of conductivity of polymer on the distribution of polarizing electric field on the ceramic particles and polymer matrix, we find that the relative high conductivity of the P(VDF- co -TrFE) may result in a high electrical field applying on the PLZT particles, which will further enhance the dielectric and ferroelectric properties of the composites. Consequently, for the combining contributions of ionic and dipole polarizations, the PLZT/P(VDF- co -TrFE) nanocomposite film with 20wt% PLZT possesses a very large dielectric constant of 85 at 100 Hz, a high ferroelectric property (D m ∼7.5 μC/cm 2 and D r ∼5 μC/cm 2 ) at a small polarizing electrical field of 37.5 MV/m, and an excellent piezoelectric constant of −31 pC/N after thermal polarizing under 5 MV/m at 100 °C, respectively. Considering their good mouldability, favorable ferroelectric and piezoelectric properties, the flexible PLZT/P(VDF- co -TrFE) film provides a reliable reference of the potential using of the ceramic/polymer nanocomposites in sensor, actuator, and other mechanical-electrical energy transforming devices. [ABSTRACT FROM AUTHOR]

Inverted bottom-emission organic light emitting diodes (IBOLEDs) have attracted increasing attention due to their exceptional air stability and applications in active-matrix displays. For gaining high IBOLED device efficiencies, it is crucial to develop an effective strategy to make the bottom electrode easy for charge injection and transport. Charge selectivity, blocking the carrier flow towards the unfavourable side, plays an important role in determining charge carrier balance and accordingly radiative recombination efficiency. It is therefore highly desirable to functionalize an interfacial layer which will perform many different tasks simultaneously. Here, we contribute to the hole-blocking ability of the zinc oxide/polyethyleneimine (ZnO:PEI) nano-composite (NC) interlayer with the intention of increasing the OLED device efficiency. With this purpose in mind, a small amount of 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi) was added as a hole-blocking molecule into the binary blend of ZnO and PEI solution. The device with a ternary ZnO:PEI:TPBi NC interlayer achieved a maximum current efficiency of 38.20 cd A−1 and a power efficiency of 34.29 lm W−1 with a luminance of 123 200 cd m−2, which are high performance parameters for inverted device architecture. The direct comparisons of device performances incorporating ZnO only, ZnO/PEI bilayers, and ZnO:PEI binary NC counterparts were also performed, which shed light on the origin of device performance enhancement. [ABSTRACT FROM AUTHOR]

In this study, poly(vinylidene fluoride) (PVDF)-based nanocomposites filled with surface-functionalized Ag@TiO2 core-shell nanoparticles were fabricated in order to achieve high dielectric permittivities. Using two phosphonic acid surfactants with differing carbon chain lengths, octyl and octadecyl phosphonic acid, the filler surfaces were modified to improve the dispersion of the core-shell filler in PVDF. The experimental results showed that the dielectric constant of the composite with fillers modified using octyl phosphonic acid (148 at 1 kHz) was almost three times that of the material with fillers modified using octadecyl phosphonic acid (58 at 1 kHz) at the same filler loading. The mechanisms of interfacial polarization between the modified core-shell filler and the polymer matrix were analyzed by introducing a circuit model based on AC impedance spectroscopy. [ABSTRACT FROM AUTHOR]

In this study, we aimed to control the optical and electrical properties of polyvinyl alcohol (PVA) in order to broaden its industrial and technological applications, which we achieved by blending PVA with polyvinyl pyrrolidone (PVP) and adding sol–gel prepared MgO nanopowder. The blended film and nanocomposite films were prepared using the solution casting technique. X-ray diffraction analyses showed that the crystallite size was ∼18.4 nm for MgO and the highest degree of crystallinity (X C ) in the films was about 24.34% at 1.0 wt% MgO. High resolution transmission electron microscopy determined the nanoribbon morphology of MgO. Scanning electron microscopy (SEM) indicated the uniform distribution of the MgO nanoribbons on the surfaces of the PVA/PVP films. SEM and Fourier transform infrared spectroscopy also confirmed the interaction between the blend and MgO fillers. The effects of the additives on the glass transition ( T g ) and melting ( T m ) temperatures were evaluated by differential thermal analysis and differential scanning calorimetry. The appearance of one melting point confirmed the miscibility of the two polymers. According to ultraviolet–visible–near infrared spectroscopy measurements, the optical properties and optical constants of PVA could be adjusted by the addition of PVP and MgO, where the optical band gap ( E g ) determined for PVA increased with the PVP content, whereas it decreased to 4.8 eV as the MgO content increased. The DC conductivity ( σ d c ) of the films increased whereas the activation energy ( E a ) decreased after the addition of MgO, possibly because the nanoribbon shape fixed the preferred conducting pathways. In addition, MgO could break the H-bond in OH groups of the blends to allow the free movement of the molecular chains. [ABSTRACT FROM AUTHOR]

The present paper deals with postbuckling characteristics of carbon nanotube reinforced composite (CNTRC) rectangular plates with integrated piezoelectric layers subjected to in-plane compressive loads. The von Karman type of geometrical nonlinearity is taken into consideration to account for the large deformations of the plate. The dispersion of CNTs may be uniform or functionally graded and the distribution of electric potential across the thickness of piezoelectric layers is simulated by a combination of linear and sinusoidal functions. Generalized differential quadrature method is employed to discretize nonlinear stability equations, boundary conditions and Maxwell equation and then nonlinear system of equations is solved using a displacement control strategy. A comprehensive parametric study is presented to provide an insight into effects of CNT dispersion and volume fraction, geometrical parameters, type of in-plane load, boundary conditions, thickness of piezoelectric layers and external applied voltages on the postbuckling behaviors of the nanocomposite plate. It is shown that snap-through type of instability, which is known as secondary instability, occurs during postbuckling regime. It is revealed that both volume fraction and dispersion of the CNTs could affect the snap-through characteristics of the plate. It is found that snap-through instability is sensitive to thickness of the piezoelectric layers. [ABSTRACT FROM AUTHOR]

A sandwich-configuration electrochemiluminescence (ECL) immunosensor based on Au star@BSA-Luminol nanocomposites for ultrasensitive determination of human chorionic gonadotropin (HCG) has been developed. In this work, nanostructured Polyaniline hydrogels (Pani) decorated with Pt nanoparticles (Pani/Pt) were utilized to construct the base of this immunosensor, greatly increasing the amount of loaded capture antibodies (Ab 1 ) via linkage reagent glutaraldehyde (GA). The used conducting Pani/Pt nanocomposites possessed the unique features, such as large surface area, high electron transfer speed and favorable electrocatalytic activities of hydrogen peroxide, which offered a prominent platform for this sandwich-sensor and acted as efficient ECL signal amplifier also. Furthermore, we employed horseradish peroxidase (HRP) to block the nonspecific binding sites instead of commonly used bovine serum albumin (BSA), which further amplified the signal of luminol in the present of hydrogen peroxide (H 2 O 2 ). In addition, Au star@BSA nanocomposites with excellent water solubility, low-toxicity and great biocompatibility were prepared and used to immobilize HCG detection antibodies (Ab 2 ) and luminescent material luminol. Then, the above-synthetized Luminol-Au star@BSA-Ab 2 complex was attached to the modified sensor by sandwiched immunoreactions. Under the optimized conditions, the proposed immunosensor exhibited a sensitive detection of HCG in a wide linear range from 0.001 to 500 mIU mL −1 with a detection limit of 0.0003 mIU/mL (S/N = 3). All the results indicated that such a sandwiched HCG immunosensor exhibited favorable ECL analytical performance. This developed method may be potentially used to recognize other clinical protein and display a novel ideal to construct an immunosensor. [ABSTRACT FROM AUTHOR]

Nanocomposite polyacrylonitrile filaments containing titanium dioxide and silver nanoparticles were produced by wet-spinning method with the aim of developing multifunctional filaments showing antibacterial activity, photocatalytic activity, and electrical conductivity. The nanocomposite filaments were characterized regarding their morphology, composition, nanoparticle dispersion, tensile properties, crystallinity, conductivity, thermal properties, photocatalytic, and antibacterial activity. The nanoparticles were observed to be well dispersed. The composite filaments with 3 wt% silver nitrate showed improved crystallinity. The highest breaking tenacity of 8.72 cN/tex was observed for the filament with 1 wt% TiO2 and 3 wt% AgNO3. The conductivity of the nanocomposite filaments were on the order of 10−4 S/cm, which is in the semiconductive range. The nanocomposite filaments displayed both antibacterial and photocatalytic activity. This study showed the possibility of producing multifunctional filaments with the simultaneous addition of different types of nanoparticles into the filament structure. [ABSTRACT FROM AUTHOR]

In this paper, we report about the preparation of novel nanocomposite films based on graphene and poly (3,4 ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). It has been observed that the prepared nanocomposite material shows excellent electrical conductivity of 60 S/cm and highly transparent (>90%) in the visible region. The resistivity of graphene and PEDOT:PSS nanocomposite films decreases as temperature increases, which is a characteristic behavior of semiconductors. The conductivity of nanocomposite film is enhanced by two orders of magnitude as compared to pristine PEDOT:PSS film. Au/graphene-PEDOT:PSS nanocomposite/ n -Si/In-Ga diodes are fabricated and it exhibited rectifying behavior. [ABSTRACT FROM AUTHOR]

Polymer-based supercapacitors (PSCs) have the potential for large-scale practical application because of their high theoretical capacitance. The effect of environmental temperature on the practical applications of PSCs and its underlying mechanism has been long neglected. In this work, a graphene-silver-polypyrrole nanocomposite was prepared by an eco-friendly hydrothermal in situ polymerization method at temperatures ranging from −45 °C to 80 °C. The ternary hybrid nanocomposites exhibited a high specific capacitance of 611.5 F g −1 /586 F g −1 at a current density of 1.0 A g −1 and a remarkable cycling stability of 93% and 82.4% capacitance retention after 3000 cycles at −45 °C and 80 °C, respectively. Furthermore, they also achieved excellent flexibility in a wide temperature range as all-solid-state supercapacitors. The outstanding electrochemical performance of the graphene-silver-polypyrrole supercapacitors in such a wide temperature range exceeds that of similar polypyrrole-based supercapacitors reported previously. [ABSTRACT FROM AUTHOR]

Al–4.5 wt.% Cu-based nanocomposites, reinforced with various weight percentages of ZrO 2 , have been synthesized via mechanical alloying method. The mixture powders were cold pressed and sintered at various firing temperatures up to 500 °C for 1 h in argon atmosphere. X-ray diffraction technique is utilized to investigate structural phases and elemental diffusion of milled powders. Transmission and scanning electron microscopies coupled with energy dispersive spectroscopy were employed to examine the morphology of milled powders and the microstructure of sintered specimens, respectively. Physical, mechanical and electrical properties of sintered samples were measured. Moreover, the sintered samples followed by heat treatments at 460 °C for 3 h, quenched and then, artificial aging was performed. The results revealed that Al 2 Cu precipitate phase was clearly observed after milling reflecting the formation of supersaturated solution of Cu in Al. Increase of ZrO 2 contents caused weakness of Al 2 Cu phase, decrease in the crystal and particle sizes. Furthermore, successive increase of ZrO 2 contents led to, in contrast to relative density and electrical conductivity, remarkable enhancement of mechanical properties of the nanocomposites. The results pointed out that microhardness, compressive strength and conductivity, for specific ZrO 2 content, obviously increased at the early stage of aging and then, decreased. [ABSTRACT FROM AUTHOR]

Poly(ethylene terephthalate) (PET) composites were loaded with four different carbon-based fillers: functionalized carbon nanotubes (CNT), exfoliated graphite (EG), and hybrid materials such as Mg(OH) 2 , which is primarily used as a flame retardant additive in plastics, dispersed over functionalized CNT and EG. The technology used to mix the different phases was high energy ball milling in dry conditions and at ambient temperature. Morphological organization, thermal and electrical properties of composites were evaluated and correlated with the type of filler. The electrical properties were analyzed over a wide temperature range, from 25 °C to 150 °C, and correlated to the starting structural organization of the composites and the morphological transformations occurred during the thermal heating. The addition of EG and CNTs to PET did not have influence on the amorphous arrangement of unfilled PET, while the loading of Mg(OH) 2 /EG and Mg(OH) 2 /CNT fillers favoured the PET crystallization. The crystallization inducted by temperature allowed an increasing in electrical conductivity of the starting amorphous samples. On the other hand, it was found a conductivity independent of temperature for semicrystalline samples (filled with Mg(OH) 2 /EG and Mg(OH) 2 /CNT). The charge transport, for the analyzed PET composites, is favoured by the higher degree of crystallinity. [ABSTRACT FROM AUTHOR]

In this work, bacterial cellulose (BC)/reduced graphene oxide (rGO) as a new class of electrical conductive nanocomposite aerogels were in-situ synthesized and dried by the supercritical CO 2 ( ScCO2) drying method. A modification has been performed on the self-consistent effective medium theory to predict overall electrical conductivity of nanocomposite aerogels. It was observed that the porosity had a distinct effect on the overall electrical conductivity of nanocomposite aerogel beneath percolation threshold, but had no effect beyond it. The latter observation was attributed to the formation of continuous pathway associated with electron tunneling effect, beyond percolation threshold. The results also indicated that in the presence of rGO, the density, specific surface area and Young ' s modulus of nanocomposite aerogel increased up to 0.025 g/cm 3 , 252 m 2 /g and 2020 MPa, respectively. Also, the gauge factor of 19 obtained for BC/rGO nanocomposite aerogel indicated the potency of fabricated nanocomposite aerogel as a strain sensor. [ABSTRACT FROM AUTHOR]

In the present work, we have investigated structural, dielectric, ac conductivity, magnetic and electromagnetic interference (EMI) shielding effectiveness (SE) performance of Co0.5Ni0.5Fe2O4 nanoparticles and Polyaniline (PANI)/Co0.5Ni0.5Fe2O4 nanocomposites for EMI shielding applications. The Co0.5Ni0.5Fe2O4 nanoparticles were synthesized by solution combustion method. PANI/Co0.5Ni0.5Fe2O4 nanocomposites were prepared by in-situ polymerization method. As-prepared samples were examined by using X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. The microstructural and composition studies have been performed using Field emission scanning electron microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) analysis. Thermal stability of the composite was analyzed using thermo gravimetric analysis (TGA). Frequency dependence of dielectric and ac conductivity (σac) studies have been undertaken on the Co0.5Ni0.5Fe2O4 nanoparticles and PANI/Co0.5Ni0.5Fe2O4 nanocomposites in the frequency range 50 Hz–5 MHz. The electrical conduction mechanism in the synthesized samples found to be in accordance with the electron hopping model. Present Co0.5Ni0.5Fe2O4 nanoparticles and PANI/Co0.5Ni0.5Fe2O4 nanocomposites exhibited hysteretic behavior under the applied magnetic field at room temperature. The maximum values 39.9 and 58.22 dB of SE at 50 Hz were obtained at room temperature for Co0.5Ni0.5Fe2O4 nanoparticles and PANI/Co0.5Ni0.5Fe2O4 nanocomposites respectively. Present Co0.5Ni0.5Fe2O4 nanoparticles decorated with PANI can be recognized as a promising functional material for the absorbing of electromagnetic (EM) waves due to large amount of dipole polarizations in the polymer backbone and at the interfaces of the Co–Ni ferrite nanoparticles and PANI matrix. [ABSTRACT FROM AUTHOR]

The porous carbon nanofibers-sulfur (PCNFs-S) composite electrode with micro-mesoporous (<10 nm) and meso-macroporous (>10 nm) is successfully designed and prepared via the electro-blown spinning technique and thermal treatment. The meso-macroporous structure in the PCNFs-S composite can provide high sulfur content up to 80 wt%, while micro-mesoporous affords efficient trapping of polysulfides and inhibits the “shuttle effect”. And the tailored porous fibrous network structure and carbon nanotubes (CNTs) in the composite facilitate the construction of a high electrical conductive pathway. Therefore, the lithium-sulfur (Li-S) batteries electrode exhibits high initial discharge capacities as high as 954 and 602.2 mAh g −1 at 0.5 C and 2 C, respectively, and can obtain quite stable capacities of 795 and 601.5 mAh g −1 after 350 cycles. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) were incorporated individually into miscible polyvinylidene fluoride (PVDF)/polyvinyl acetate (PVAc) blend to obtain ternary nanocomposites. Optical and electron microscopy images showed that the CNTs were more randomly dispersed within the blend matrix than the GNPs. DSC results illustrated that the CNTs exhibited higher nucleation efficiency than the GNPs for PVDF crystallization in the composites. In addition, the CNTs more evidently accelerated the isothermal crystallization of PVDF in the composites than the GNPs. The presence of PVAc decreased the melting temperature of PVDF; GNP or CNT addition induced higher PVDF melting temperatures than the blend. XRD results demonstrated no change in α -form crystals of PVDF in the blend and composites. The thermal stability of PVDF in the blend was improved after GNP or CNT incorporation; GNPs produced slightly more improvement than CNTs. The storage modulus (rigidity) of 1.5 phr CNT- or GNP-added composites increased by 28.7% or 73.8% (at 25 °C), respectively, compared with that of the blend matrix. The presence of either GNPs or CNTs reduced the electrical resistivity of the parent blend, with the CNTs exhibiting evidently higher efficiency than the GNPs. The electrical and rheological percolation thresholds ((pseudo)network structure development) of the CNT-added composites were determined at 0.3–0.5 phr and 1 phr loading, respectively. The GNP-added composites showed no percolations due to lesser random dispersion of GNPs within the blend matrix. [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNTs) are known for improving the mechanical and electrical properties of polymers. The dispersion state of MWCNTs in the polymer matrix is critical for the fabrication of high-performance nanocomposites. Here, we show a simple strategy for tuning the dispersion state of MWCNTs in poly(ε-caprolactone) (PCL) via graphene oxide (GO) nanosheets and to further balance electrical and mechanical properties of the PCL/MWCNT nanocomposites. The strong π-π interactions between MWCNTs and GO nanosheets lead to easy adsorption of MWCNTs on GO nanosheet surfaces to form GO/MWCNT hybrids that retard the aggregation of MWCNTs in PCL. Furthermore, the GO/MWCNT ratio could also affect the dispersion of GO/MWCNT hybrids in PCL. Three different dispersion states of MWCNTs were found in the PCL matrix, i.e. PCL/MWCNT, PCL/GO/MWCNT (1/4) and PCL/GO/MWCNT (2/1) nanocomposites that represented severe, low and almost no aggregation of MWCNTs, respectively. The GO/MWCNT hybrids with a 2/1 ratio showed better dispersion in PCL matrix than the hybrids with a 1/4 ratio and pristine MWCNTs. The PCL/GO/MWCNT nanocomposites with almost no aggregation of GO/MWCNT (2/1) hybrids exhibited the highest tensile strength and elongation at break in comparison to the PCL/GO/MWCNT (1/4) nanocomposites and PCL/MWCNT nanocomposites. However, the best electrical conductivity was achieved in the PCL/GO/MWCNT (1/4) nanocomposites due to the low aggregation of MWCNTs. [ABSTRACT FROM AUTHOR]

Recently, nickel ferrite with high theoretical capacity over the other metal oxide has been applied as electrode material for batteries and supercapacitors. However, owing to the serious aggregation and low specific surface area, the electrochemical performance of nickel ferrite (NiFe 2 O 4 ) should be in urgent need of improvement. Here, we report the synthesis of unique molybdenum dioxide (MoO 2 ) and nickel ferrite composite (MoO 2 /NiFe 2 O 4 ) material via a facile strategy for the first time. The composite material presents a nanosheets-nanocrystals heterostructure. When evaluated as an electrode for hybrid supercapacitor in an alkaline solution, the MoO 2 /NiFe 2 O 4 composite material presents a greatly enhanced specific capacity (2105 mA h/g at 4 A/g), which is better than those of individual component and exceeds some of the reported MoO 2 and NiFe 2 O 4 based electrodes. The capacity retention of MoO 2 /NiFe 2 O 4 composite is about 81.1% after 1900 cycles. Such composite material also has great potential in other energy storage and conversion system. [ABSTRACT FROM AUTHOR]

In this paper, poly(vinyl alcohol) (PVA)/poly(dopamine)-functionalized graphene oxide (PGO) nanocomposites with high performance were prepared by an environment-friendly and facile strategy. GO was firstly functionalized and simultaneously reduced by poly(dopamine) to yield PGO. Then it was mixed with PVA in aqueous solution to make PVA/PGO nanocomposites. Transmission electron microscopy revealed that the PGO nanosheets are well dispersed and randomly oriented throughout the PVA matrix. At the same time, the thermal properties and water barrier properties of the PVA/PGO nanocomposites have been strikingly enhanced by the incorporation of PGO. The degradation temperature of the nanocomposites is more than 30 °C higher than that of pure PVA by the addition of 0.7 wt% PGO, which shows good thermal stability. The water vapor permeability of the nanocomposites also decreases to 0.71 × 10 −12 g cm/(cm 2 s Pa), corresponding to 80% reduction than that of pure PVA. Moreover, the PVA/PGO nanocomposites also present enhanced conductive properties. The PVA/PGO nanocomposites with such outstanding properties show great promising applications in the fields of packaging, electronics, fuel cell industry, fiber, and so on. [ABSTRACT FROM AUTHOR]

Quasicrystal, an attractive type of material with special physical and chemical properties, has been considered as one of the most promising functional materials. Herein, Al 65 Cu 23 Fe 12 quasicrystal precursor alloy ribbons were prepared by arc-melting subsequently melt-spinning under a protective argon atmosphere. Unique Fe 3 O 4 /CuO/Cu with bicontinuous ligaments and nanopore channels structure was fabricated by a facile one-step chemical dealloying method in 2 M NaOH solutions at room temperature with controlled dealloying times (12 h, 24 h, 48 h, and 96 h). X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) analysis, transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM) are employed to study the crystal structure and microstructural evolution of these Fe 3 O 4 /CuO/Cu composites. The unique composites combined both advantages of Fe 3 O 4 /CuO with high capacities and Cu with excellent conductive as anode material for lithium ion batteries. Remarkably, the successful integration of Fe 3 O 4 , CuO and Cu as well as the specific 3D ligament-pore structure, which could alleviate the volume changes during the repeating charge and discharge cycles, endowed the as-prepared electrode material with higher reversible capacity, excellent cycle life, and good rate performance due to the synergetic effect. Cyclic voltammetry (CV) and galvanostatic charge–discharge measurements had been aimed at evaluating the lithium storage performances of the Fe 3 O 4 /CuO/Cu composites. A high specific capacity of 738.4 mAh g −1 could be achieved up to 550 cycles at a current density of 200 mA g −1 . Therefore, the as synthesized Fe 3 O 4 /CuO/Cu composites exhibit excellent electrochemical stability and reactivity, which might open a new avenue to explore the application of quasicrystals. [ABSTRACT FROM AUTHOR]

Interfacial interaction is one of the key factors to improve comprehensive properties of polymer/inorganic filler nanocomposites. In this work, a new interfacial interaction called electron transferring interaction is reported in the nitrile-butadiene rubber/halloysite nanotubes (NBR/HNTs) nanocomposites. The X-ray photoelectron spectroscopy (XPS) and in-situ controlling temperature Fourier transform infrared spectroscopy (FTIR) have confirmed that electrons of electron-rich −CN groups in NBR can transfer to the electron-deficiency aluminum atoms of HNTs, which packs a part of NBR molecules onto the surface of HNTs to form bound rubber and stabilize the homogeneous dispersion of HNTs with few agglomeration as revealed by scanning electron microscope (SEM) and dynamic mechanical analysis (DMA) performances, even at high HNTs addition, resulting in high light transmittance. The tensile strength of NBR/30wt%HNTs nanocomposites is about 291% higher than pure NBR, without sacrificing the elongation at break. [ABSTRACT FROM AUTHOR]

NiFeO and LiNiFeO/NiFeO nanocomposite samples are prepared using citric acid and urea assisted combustion process. The prepared pristine and nanocomposite samples are characterized by using powder X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy techniques. The effect of LiNiFeO on the LiNiFeO/NiFeO crystallite size and associated strain is calculated using Williamson-Hall plot. The effect of LiNiFeO on the electrical and dielectric properties of the composite samples are analyzed using AC-impedance spectroscopy. The prepared composite materials exhibit mixed electrical conduction behavior, and the conduction is due to lithium ion migration as well as electron hopping between Fe and Fe ions in the spinel structure. The conductivity gradually increases and attains maximum upon lithium ion inclusion in the composite. The further increment of lithium ion doping decreases the conductivity. [ABSTRACT FROM AUTHOR]

In this research (PANI/CNT) core/shell nanocomposite were synthesized via in situ chemical oxidative seeding polymerization‚ the results of SEM indicated the structure of synthesized nanocomposite. TEM‚ FTIR‚ UV–Vis‚ XRD analyses of samples showed that this nanocomposite is decorated with (Fe‚ Co) oxide nanoparticles. The VSM test of as prepared and annealed nanocomposite exhibited the saturated magnetization of 1.1 and 3.86 emu/g, respectively; the coercivity values were also − 350 and − 110 Oe, respectively. The reflection loss characteristics of (Fe‚ Co) oxide–Pani–CNT core/shell nanocomposite were also investigated with a vector network analyzer‚ in the 8.2–12.4 GHz range (X band). The maximum absorption increases with enhancement of the dispersed nanoparticles percent in polyurethane matrix from 1 to 10%. The value of the maximum reflection loss in the absorption samples with 1 and 10% of nanoparticles is − 2.14 dB at 9.33 GHz and − 7.32 dB at 11.97 GHZ, respectively. [ABSTRACT FROM AUTHOR]

ZnO-NiO nanocomposites thin films were elaborated at different mixing concentrations using sol gel and spin coating methods. Their structural and morphological evolutions as well as the optical and electrical properties were investigated. XRD diffraction and Raman spectra allowed phase identifications of ZnO (zinc oxide) and NiO (nickel oxide) with no appearance of secondary phases and the crystallinity of elaborated nanocomposite films improved with doping concentration increase. The grain sizes of obtained ZnO-NiO nanocomposites are investigated by AFM (Atomic force microscopy); they increase in the range (10–65 nm) and they are observed to affect the optical and electrical properties. In fact, ZnO-NiO nanocomposites thin films optical reflectivity decreased in the range (10–5%) with the increasing of mixing proportion and their resistivity decreased up to 1.4 10 2 Ω cm. The optical band gaps were in the range (3.3–4 eV). The values obtained by UV–Vis spectroscopy and ellipsometry are quite similar. We remarked also that the NiO concentration increase on to the nanocomposite induced a red shift of the gap value while the ZnO increase led toward a blue shift [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis of Mg(OH) 2 NPs and Mg(OH) 2 –rGO nanocomposites (NCs) by microwave assisted co-precipitation method. The crystal phase, structural morphology and functional groups of the as-synthesized samples were analyzed by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR). Raman spectroscopy was used to study the defects in the samples. Raman spectroscopy and the SEM results validate the growth of Mg(OH) 2 NPs on the rGO nanosheets. The chemical composition of the prepared samples was analyzed by EDAX. Optical properties of the as-synthesized samples were studied by UV–visible spectroscopy and the energy band gap was calculated by Tauc relation which shows a decrease in band gap with an increase in the amount of Graphene Oxide (GO) in the NCs. The dielectric properties were studied as a function of frequency over a range of 50 Hz to 5 MHz at room temperature. The value of dielectric constant decreases with an increase in frequency, this could be due to the existence of a polarization process at the border of the rGO sheets and Mg(OH) 2 NPs. The value of dielectric loss shows a decreasing trend with an increase in frequency whereas the larger value of AC conductivity in Mg(OH) 2 –rGO NCs as compared to Mg(OH) 2 NPs approves the restoration of sp 2 network in the graphene sheets. [ABSTRACT FROM AUTHOR]