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Abstract Co x Zn 1-x O (x = 0.01, 0.05 and 0.1) nanoparticles were prepared by microwave-assisted polyol method from zinc acetate dihydrate and Co(II) acetylacetonate. The reactions were performed in diethylene glycol (DEG) at 250 °C with the use of oleic acid as a surfactant. Resulting nanoparticle (ca. 10 nm) precipitates were washed with methanol and dried or kept as colloidal solutions redispersed in toluene. Colloidal solutions were mixed with the Poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) polymer to produce thin nanocomposite layers with specific optoelectronic properties. The electronic structure in terms of density of states (DOS) of MEH-PPV and MEH-PPV/nanocomposite layers was investigated by recently proposed energy resolved electrochemical impedance spectroscopy method. The MEH-PPV polymer and its nanocomposites with ZnO or Co x Zn 1-x O nanoparticles were used as thin active layers in polymer light emitting diodes (PLED). The nanocomposite layers exhibited optoelectronic properties which were found to be beneficial as the active layer in PLEDs, exhibiting an order of magnitude enhancement in electroluminescence intensity. A pronounced effect on the opening bias voltage of final devices with Co x Zn 1-x O nanoparticles was also observed. Graphical abstract Image 1 Highlights • Original facile microwave-assisted synthesis of Co x Zn 1-x O nanocolloids is reported. • Solution of MEH-PPV polymer and Co x Zn 1-x O nanodispersions mix without precipitation. • MEH-PPV/Co x Zn 1-x O composite layers electronic structure mapping by ER-EIS technique. • PLEDs with MEH-PPV/Co x Zn 1-x O nanocomposite active layer were successfully prepared. • The PLEDs with MEH-PPV/Co x Zn 1-x O layer exhibited lowering of opening bias voltage. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel method (energy resolved-electrochemical impedance spectroscopy) for the characterization of the electronic structure of nanocomposite thin film, which serves as an active layer in prepared PLEDs, is used. • Two kinds of nanoparticle addition effects were investigated. • (A) Non-specific modification of the polymer chain packing ordering results into polymer electronic structure alteration. • (B) Specific roles connected with the electronic structure of the particles, their conductivity and doping contribution to the electronic structure of the emissive layer. The work is focused on power efficiency and luminance of polymer light-emitting diodes (PLED) based on polymer matrix and nanoparticulate filler. As polymer matrices poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) were used. Nanofillers, aluminium-doped ZnO nanoparticles, were prepared by microwave-assisted polyol method and characterized by XRD, SEM, and TEM. Obtained nanoparticle colloids were mixed with dissolved polymer. Then, nanocomposite active layers of prepared PLEDs were spin-cast in one processing step. Specific optoelectronic and electric properties of nanocomposite materials and performance of PLED devices were investigated using UV–Vis absorption, photoluminescence, energy-resolved electrochemical impedance spectroscopy (ER-EIS), and I-V and luminance measurements. The addition of Al-doped ZnO nanoparticles improved power efficiency of diodes exhibiting an order of magnitude enhancement in electroluminescence intensity, luminance (from 1 900 to 20 700 cd/m2 for MEH-PPV and from 4 600 to 38 000 cd/m2 for F8BT) and had pronounced effect on opening bias voltage of final devices. In addition, two effects of nanoparticulate doping were revealed. The first, specific one, related with electronic structure of used nanoparticles. The second, non-specific, which indirectly contributes to structural ordering of the polymer matrix. Observed phenomena are related to electronic band structure affected by the addition of nanoparticles as revealed by ER-EIS. [ABSTRACT FROM AUTHOR]

Abstract This paper demonstrates a three-dimensional electromagnetic interference shielding nanocomposite flexible sheet which is consisted of NiFe 2 O 4 spinel ferrite nanoparticles, and carbon source materials such as graphite, graphene oxide and reduced graphene oxide in the elastomer matrix. The prepared nanocomposite exhibited ferromagnetic behavior. The total shielding effectiveness was up to 28.5 dB for the elastomer nanocomposite sheet having filler NiFe 2 O 4 nanoparticles with reduced graphene oxide. The coexistence of electric and magnetic dipoles in the prepared shielding nanocomposite sheet can response highly to electromagnetic waves and consequently high electromagnetic loss. The high value of shielding efficiency is also related to dual interfaces of NiFe 2 O 4 and reduced graphene oxide in the ternary NiFe 2 O 4 -Reduced Graphene Oxide-Elastomer nanocomposite. The investigated results indicate that the absorption attenuation is a dominant mechanism for electromagnetic interference shielding. The current study demonstrates a facile strategy to develop advanced lightweight electromagnetic interference shielding nanocomposite flexible sheet. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Composite materials based on PLA have been studied in depth for many applications, including food packaging. This manuscript describes extensive research conducted on a biodegradable polymer (PLA), inorganic filler (CaCO 3), and polyester-based plasticizer (PEP, based on a copolymer of low-molecular-weight PLA and PEG) prepared under semi-industrial conditions, as applicable for the packaging of hot food. The properties of the composite were achieved by post-processing annealing, notably its thermal stability, thereby permitting contact of the material with hot food. The manner of processing was deemed suitable for deployment at an industrial scale, moreover, the thermal stability of the final product endured, evidencing its applicability for such packaging. Change in the morphology of the structure of the composite material depended on the composition and annealing process, as detailed herein. The effect of the post-production thermal annealing on the molecular weight of samples was studied using the gel permeation chromatography. The thermal properties of the composites were investigated by differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The crystallinity was assessed using X-ray diffraction technique, while mechanical behavior was tested in relation to the given tensile properties, shape stability at high temperature, and permeability by the transmission rates of gas/water vapor. [Display omitted] • PLA composite with CaCO 3 and plasticizer was prepared under semi-industrial conditions with a post-processing annealing. • The properties of the composite depended on the morphology and volume fractions of the crystalline and amorphous regions. • The two additive components and given technological conditions lends shape stability to the composite. • The composite was suitable for contact with hot food or use as packaging for foodstuffs that are heated in microwave ovens. [ABSTRACT FROM AUTHOR]

Abstract: The Cu–Ni nanoalloy phase diagram respecting the nanoparticle size as an extra variable was calculated by the CALPHAD method. The samples of the Cu–Ni nanoalloys were prepared by the solvothermal synthesis from metal precursors. The samples were characterized by means of dynamic light scattering (DLS), infrared spectroscopy (IR), inductively coupled plasma optical emission spectroscopy (ICP/OES), transmission electron microscopy (TEM, HRTEM), and differential scanning calorimetry (DSC). The nanoparticle size, chemical composition, and Cu–Ni nanoparticles melting temperature depression were obtained. The experimental temperatures of melting of nanoparticles were in good agreement with the theoretical CALPHAD predictions considering surface energy. [Copyright &y& Elsevier]