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SiO2 has been widely used in the assembly of photonic crystals due to its excellent optical properties. Currently, many studies have been focused on the structural color of monodispersed silica photonic crystals, yet there are few reports on the poly-dispersed ones. In this study, SiO2 particles (450～650 nm) with normal size distribution was prepared by the improved St9ber method. Pouring self-assembly method was used for the film fabrication. Polyvinyl alcohol (PVA) with flexible macromolecular chains was introduced into the gap of SiO2 microspheres, and polyvinylpyrrolidone (PVP) with strong polar groups was introduced into the surface of the microspheres to enhanced film flexibility and better orderliness respectively. It was found that integral film is shown while the mass ratio of 0. 3% SiO2 to 8% PVA is 2∶1. Best iridescent film is shown at the PVP dosage of 1. 75%. The film fabricated in this paper has flat surface and good mechanical properties. The large and small silica microspheres are arranged alternately to form different photonic band gap, which results in iridescent color under point light, while colorless and transparent under natural light. The research results will provide potential application in optical anti-counterfeiting, optical encryption and decoration. [ABSTRACT FROM AUTHOR]

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Zinc vanadate micro/ nano materials are multifunctional, with good stability, high chemical activity, and high visible light transmittance. The properties and application fields of the materials are closely r elated to their morphology and size. Therefore, controllable synthesis of zinc vanadate micro/ nano materials is particularly important. In this study, zinc vanadate with nano disk, nanorod and micron flower structure was prepared by SDS assisted hydrothermal method with sodium metanovadate and zinc acetate as raw materials. The effect of surfactant, pH, hydrothermal temperature and time on the morphology of zinc vanadate were investigat ed. The electrochemical properties of zinc vanadate with different morphologies were studied by preparing electrodes with different morphologies as active substances. The results show that the optimal dosage of SDS is 8 %, and lower pH is favorable for the formation of discoid structure, while higher pH is favorable for rod-like structure. When the hydrothermal temperature is raised to 180 °C, the lamellar zinc vanadate self-assembles to form micron flower structure. Compared to the nano-disk and nanorod morphology, zinc vanadate with flower morphology has the best electrochemical properties, and its rate capability is 64%. After 1 000 cycles, the capacitance retention rate of the micron flower is still 86% of the initial value. Therefore, zinc micron flower vanadate is a potential material for supercapacitors. [ABSTRACT FROM AUTHOR]

Nano-copper can be easily oxidized in the air. The preparation of Ag@Cu core-shell structure by covering the surface of copper with silver is one way to improve its anti-oxida tion performance, which can broaden its use in electronic pastes, electromagnetic shielding materials and catalysts. In this study, glucose (C6H12O6) was used as reducing agent. Polyvi nylpyrrolidone (PVP) as dispersing agent and different complexing agents were used to re duce silver nitrate (AgNO3), finally the Ag@ Cu core-shell structure with uniform particle size and good performance was obtained. The effects of nano-copper pretreatment, different complexing agent.pH. the dosage of silver nitrate and glucose on the structure and perform ance of Ag@Cu were studied. When nano-copper was washed three times with 5% dilute sul furic acid and deionized water. the molar ratios of C6H12O6 and PVP to AgNO3 were 4 :3,8:3,2: 1,respectively, with pH of 9. 5~10 regulated by ethylenediamine,the Ag@Cu structure with relatively uniformIparticle size of around 100 nm and excellent conductivity of about 3.8 X 10 2 cm can be obtained, and good thermal stability is maintained in the range of 81 ℃~400℃. [ABSTRACT FROM AUTHOR]

Based on the original Stöber method, a multi-step addition method was applied to control the nucleation and growth rate of nano silica (SiO2), avoiding secondary nucleation and agglomeration. Then the size-controllable and highly monodispersed microspheres with smooth surface are prepared, and the size distribution is narrow, ranging from 120 nm to 530 nm. The effect of precursor adding method, precursor dosage, catalyst dosage and reaction temperature on the size and morphology of SiO2 was explored. And the relationship between the structural color of photonic crystals and size of SiO2 particles is obtained through investigation . The structure and optical properties of the samples were characterized b y XRD, SEM, FT-IR and UV-VIS-N IR. It is shown that the particle size of silica decreases with the increase of temperature, but it increases with the higher precursor concentration or ammonia dosage. The band gap of photonic crystals is in the visible light region, and the reflection peak gradually redshifts with the increase of particle size. There may be certain shifts of bandgap position due to some unavoidable defects. [ABSTRACT FROM AUTHOR]

The aqueous acrylic resin, aqueous acrylic emulsion, the auxiliary agent and deionized water are uniformly mixed in a certain ratio, then the prepared AgNWs/PVP(silver nanowires/Polyvinylpyrrolidone) composite is added with certain amount of water and ethanol, finally a AgNWs/aqueous acrylic conductive ink is obtained after grinding. The effect of different conditions on the ink performance is explored. The mixture of 15% AgNWs, 25% acrylic resin and 60% other materials is ground for 15 min and coated on coated paper, then dried at 150 °C for 30 s, it is found that the square resistance is as low as 0. 176 Ω/□ and the coated surface is flat. While the sintering temperature is ranging from 100 °C to 150 °C, the conductive coating still has good conductivity after 2 000 times of rubbing, or 40 times of tearing, or 1 000 times of bending resistance. [ABSTRACT FROM AUTHOR]

Silver nanowires(AgNWs)are good for conductive ink and flexible transparent conductive film, due to its high transmittance and good conductivity. The performance of silver nanowires with small diameter and high aspect ratio is better than that of silver nanowires, therefore it is necessary to discuss the preparation process and technology. In this paper, a simple solvent thermal method was used for the preparation of small diameter and homogeneous silver nanowires, using silver nitrate as a silver source, ethylene glycol(EG)as a reducing agent, polyvinylpyrrolidone(PVP)as a growth agent, and hexahydrated nickel chloride(NiCl2·6 H2O)as a control agent. The effects of reaction time, concentration of nickel chloride and PVP/AgNO3 molar ratio on the microstructure of silver nanowires were investigated. It was found that silver nanowires with smallest diameter(25~35 nm)and highest aspect ratio(1 000)were prepared when the concentration of NiCl2 was 200μmol/L, reaction time was 10 h, and PVP/AgNO3 molar ratio was 2. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)