Synthesis of an Organic–Inorganic Hybrid Polymeric Material and Its Adsorption Performance Characterization Toward Acrylamide

An organic–inorganic hybrid functionalized material was successfully synthesized by a surface molecular imprinting technique combined with a nonhydrolytic sol–gel process using acrylamide as the template, methacrylic acid as the functional monomer, methacryloxypropyltrimethoxysilane as the cross-linker, and magnetic chitosan microspheres as the support material. The adsorption ability and selectivity of this material toward acrylamide was characterized. Experimental results showed that the imprinted polymer exhibited better recognition and selective performance toward acrylamide than the nonimprinted polymer. The saturated binding capacity (Q _max) was 104.68 mg/g, and the equilibrium dissociation constant was 263.16 mg/mL. This prepared material also offered fast kinetics for the adsorption and desorption of acrylamide. After shaking for 5 min, an adsorption capacity of 4.71 mg/g was obtained, and it almost reached the adsorption equilibrium within 90 min.     

Co–In2O3 Nanocomposite Films: Synthesis and Structural and Magnetic Properties

Physics of the Solid State - The structural and magnetic properties of granular Co–In2O3 nanocomposite films formed by vacuum annealing of In/Co3O4 film bilayers at a temperature of...     

Synthesis and Characterization of New Organic–Inorganic Hybrid Nanosilica Fillers Prepared by Sol–Gel Reaction

In light of the success of making multicomponent sol–gel glasses, in this study the synthesis of new hybrid nanosilicas with controlled hydrophilic/hydrophobic properties was carried out by incorporating organic based species with appropriate functional groups to inorganic based alkoxides by co-condensation reaction. Furthermore, in this study the acidity and the water content during reaction synthesis was proven to be critical in controlling the structure of the hybrid nanosilicas. These nanosilicas with different hydrophobicity were obtained by using TEOS (tetraethylorthosilicate) and 10 wt% two organic modifiers (tris-hydroxymethylaminomethane — TRIS — and 1,1,1,3,3,3-hexamethyldisilazane-HDMS). The average diameter of the nano-particles ranged between 7 and 10 nm. The addition of the organic modifiers changed the pH of the hybrid nanosilicas, to a different extent depending on the nature of the organic modifier. The hydrophobicity in the hybrid nanosilicas estimated from pH measurements in water and ethanol, and from IR spectroscopy, can be tailored by incorporating different organic modifiers on the network during synthesis. Finally, the measurement of pH of the hybrid nanosilicas by using solvents with different polarity/acidity was a simple and efficient method of assessing the hydrophobicity of the nanosilicas.     

Synthesis and Structure of Magnetic Core-shell Ni–Ce Nanocomposite Particles

A new type of magnetic core-shell Ni–Ce nanocomposite particles (15–50 nm) is presented. SEM observations suggest the particles are strongly ferromagnetic, interacting with ordered chain-like features. Typical HR-TEM images demonstrate that many planar defects (nanotwins and stacking faults) exist in the surface shell and large Ni core zone (10–40 nm) of the particles; the inner shell layers (4–6 nm) consist of NiCe alloy and the outermost shell is NiO. Nano-diffraction patterns show an indication of well-defined spots characteristic of nanocomposite materials, of which certain crystal facet orientation relationships between orthorhombic [111] of NiCe and cubic [311] of Ni₂Ce, face-center crystal [222] of NiO, cubic [111] of nickel have been identified. This confirms the nature of this core-shell nanocomposite particle.     

Preparation of Organic–Inorganic Multifunctional Nanocomposite Coating via Sol-Gel Routes

The inorganic–organic nanocomposite coatings are prepared on poly(methyl methacrylate) (PMMA) substrate by the spinning technique which involves incorporating homogeneously nanosized ZnO particle into the molecular inorganic–organic hybrid matrices. The hybrid matrices are derived from tetraethoxyasilane (TEOS) and 3-glycidoxypropyltrimethoxyailane (GLYMO). To avoid the destruction of the polymer structure caused by ZnO and modify the interface between nanoparticles and organic groups, ZnO was first surface-coated with SiO₂ from hydrolyzed TEOS using ammonia water as catalyst. The coatings thus obtained are dense, flexible, abrasion resistant and UV absorbent.     

Polymer–Salt Synthesis of Yb:YAG Nanopowders and Study of Their Structure and Luminescent Properties

Optics and Spectroscopy - Nanopowders of ytterbium-doped yttrium aluminum garnet are synthesized by the polymer–salt method and their crystal structure and spectral-luminescent properties are...     

Synthesis and Optical Properties of ZnO Nanostructures

ZnO nanostructures with different morphologies were fabricated by changing the partial oxygen pressure. The structures, morphologies and optical properties of ZnO nanostructures were investigated by x-ray diffraction, field emission scanning electron microscopy and photoluminescence (PL) spectra at room temperature. All the samples show preferred orientation along the c-axis. The oxygen partial pressure and the annealing atmosphere have important effect on the PL property of ZnO nanostructures. The high oxygen partial pressure during growth of samples and high-temperature annealing of the ZnO samples in oxygen can increase oxygen vacancies and can especially increase antisite oxygen (OZn) defects, which degraded the near band-edge emission. However, the annealing in 1-12 can significantly modify the NBE emission.     

Study of Nonlinear Optical Properties of Organic Material Utilizing Two－color Z－scan

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Synthesis of Polyethylene Glycol–Chitosan–Nano Ag Composites and their Antibacterial Properties

Journal of Applied Spectroscopy - This study showed the synthesis of polyethylene glycol–chitosan–nano Ag (PEG–Chi–Ag) composites to improve the homogeneous distribution of...     

Preparation and Optical Properties of SnO2／SiO2 Nanocomposite

SnO2/SiO2 nanocomposites have been prepared by the soaking-thermal-decomposing method, tin oxide nanoparticles are uniformly dispersed in the mesopores of silica. The optical absorption edge of the obtained nanocomposite presents a redshift compared with bulk tin oxide, With the increasing annealing temperature during the procedure of the sample preparation, the optical absorption edge of the sample moves to shorter wavelength (blueshift). These optical properties can be ascribed to the amorphous structure and band defects of surface layers of the tin oxide nanoparticles.     

First-Principles Study of Structural and Electronic Properties of Layered B2CN Crystals

Based on the hexagonal BN structure, six possible layered B~ CN structures are constructed. Their total energies, lattice constants as well as electronic properties are calculated using the ab initio pseudopotential density functional method within the local density approximation. The calculated results show that the B2 CN-V configuration with AA stacking sequence is the most stable among the six B2CN layered structures. The characteristics of electronic structures indicate that the B2 CN-V shows metallicity, which mainly comes from -B1-C-B1-C- chains.     

La0.8Sr0.2Ni0.4Fe0.6O3–Ce0.8Gd0.2O2–δ Nanocomposite as Mixed Ionic–Electronic Conducting Material for SOFC Cathode and Oxygen Permeable Membranes: Synthesis and Properties

Mixed ionic–electronic conducting nanocomposite La_0.8Sr_0.2Ni_0.4Fe_0.6O₃ (LSNF)–Ce_0.8Gd_0.2O_{2– δ} (GDC) was prepared via ultrasonic dispersion of nanocrystalline powders of perovskite and fluorite oxides in water with addition of surfactant, followed by drying and sintering up to 1300°C. Analysis of the real structure of nanocomposite (studied by XRD and TEM with EDX) and its surface composition (studied by XPS) revealed moderate redistribution of elements between phases favoring their epitaxy. Results of impedance spectroscopy, oxygen isotope exchange, O₂ TPD and H₂ TPR experiments revealed a positive effect of composite interfaces on the oxygen mobility and reactivity agreeing with the ambipolar transport behavior of MIEC composite. Preliminary testing of button-size cell with functionally graded LSNF–GDC cathode layer supported on thin YSZ layer covering Ni/YSZ cermet demonstrated high and stable performance, which is promising for its practical application.     

Organic–inorganic nanocomposite films made from polyurethane dispersions and colloidal silica particles

Polyurethane/silica nanocomposites were prepared by solution blending of polyurethane water dispersion (PUD) based on polycarbonate macrodiol with colloidal silica aqueous sol LUDOX TMA. Because of mixing PUDs made from linear polyurethane with the nanofiller, only physical polymer/filler type of interface formed by hydrogen bonds was obtained. As a result the materials were possible to reuse after dissolution in acetone followed by dispersion in water. The effect of colloidal silica content on mechanical, thermal, morphological, and swelling properties of obtained films was tested by tensile test, dynamic mechanical thermal analysis, thermogravimertic analysis, scanning electron microscopy, atomic force microscopy, and swelling analyses. The nanocomposites were classified in three groups differing in the internal structure and functional properties: organic matrix filled with inorganic nanofiller (up to 10 wt% of silica), bicontinous systems (25 and 32 wt% of silica) and inorganic matrix filled with polyurethane (50 and 60 wt% of silica). Only small amount of colloidal silica (up to 10 wt%) improves thermo-mechanical properties, smoothes the materials, and suppresses extent of swelling without changing of the films transparency.     

Traps in the Nanocomposite Layer of Silicon–Silicon Dioxide and Their Effect on the Luminescent Properties

Physics of the Solid State - The traps of charge carriers in thermal films of silicon dioxide and silicon dioxide with a nanocomposite layer consisting of silicon oxide and silicon nanocrystallites...     

Enhanced Nonlinear Absorption and Optical Limiting Properties of Organic Material ZnTBP—CA—PhR in a DA—ET System

Nonlinear absorption of the organic material Zn-tetrabenzoporphin-cronicacid-phenonxy resin(ZnTBP-CA-PhR) in the donor-acceptor energy-transfer(DA-ET) system is investigated by the irradiation of Ar^ laser on its solid film.A reverse saturable absorption and an enhanced second reverse saturable absorption called the rereverse saturable absorption are observed in a visible wavelength range.The high performance of optical limiting of the sample possessing low input threshold and an over 95% linear transmission ratio are observed.The physical mechanism of rereverse satruable absorption is analysed by a five-level rate-equation simulating.According to the Huygens wave diffraction principle and the combination of Kerr effect,thermo-optic effect and optical absorption variation,a mathematical model for the optical limiting of ZnTBP-CA-PhR film limiter is established and the theoretical simulating gives a good agreement with the experimental results.     

Synthesis and Characterization of Sol–Gel-Derived SiO2–CaO Particles: Size Impact on Glass (Bio)Properties

Four highly bioactive glasses in a binary SiO₂–CaO system are prepared following a sol−gel method using Ca(OH)₂ as a calcium precursor. In the synthesis of glass according to the modified Stöber method, Ca(OH)₂ suspended in polyethylene glycol allows the elimination of the presence of calcite and the increase of ammonia concentration causes formation of spherical particles with different sizes in the range of 26–266 nm. The relation among the size and properties, including bioactivity, of the glass particles is evaluated. New glasses that vary in composition (10–25 wt% CaO), porosity (15–113 m² g⁻¹), and hydroxyl groups content greatly enhance the formation process of hydroxyapatite (HA) in simulated physiological fluids. For all glasses, superior apatite-mineralization ability in time as short as 2 h in the physiological-like buffer is achieved, thus exceeding the bioactivity of the known bioactive glasses, including 45S5 glass (Bioglass). The assessment of the safety and toxicity profile of the obtained glasses is verified in a wide range of concentrations (1–1000 µg mL⁻¹) against human dermal fibroblasts and MC3T3 mouse osteoblast precursors, but also to human erythrocytes by determining hemocompatibility. Two glasses of different sizes, 73 and 266 nm, are promising and warrant further research.     

Synthesis and Luminescent Properties of 1,4,5-Triphenylimidazole‒Phenothiazine Fluorophores

Two blue donor–acceptor fluorophores with 1,4,5-triphenylimidazole as the electron-transporting unit and phenothiazine as the hole-transporting unit were synthesized by grafting 1,4,5-triphenylimidazole moieties onto 3- and 3,7-position of the phenothiazine core and characterized by spectroscopic methods. Their thermal stability, photophysical, electrochemical and electroluminescence properties were systematically investigated. These compounds exhibit good thermal stability and show blue emission in dichloromethane solution and thin solid films. The solution-processed doped devices were fabricated by using these fluorophores as the emitting dopant in 1,3-bis(N-carbazolyl)benzene host, in which the device fabricated from the fluorophore containing two 1,4,5-triphenylimidazole moieties exhibited blue emission with a luminance of 648 cd/m² and external quantum efficiency of 1.48%.

     

Bulk-Quantity Synthesis and Conductive Properties of Comb-Like Dendritic ZnO Nanostructures

Adopting a simple low-temperature (-500℃) vapour process, we have synthesized bulk quantity comb-like dendritic ZnO nanostructures in large area. An atomic force microscope equipped with Au-coated probes was employed to elucidate the current-voltage characteristic of the individual ZnO nanocomb. The connection electrodes were defined by depositing Pt wires using focused ion beam (FIB). A rectification effect was observed,while it was slightly suppressed compared with that of the previous reports. The good conductive properties of the sample can be attributed to the Ga ions implantation through the FIB process of electrode definition. We suggest that the material and the FIB method can be developed to fabricate novel nanosized devices.