碳纳米管及其批量制备研究进展

从碳纳米管的优异性能和应用出发,综述了碳纳米管的制备方法以及我国目前在碳纳米管研究中面临的问题;分析了碳纳米管产业化对的我国纳米技术产业化发展的积极意义,特别介绍了清华-南风纳米粉体产业化工程中心开发的、具有我国自主知识产权的纳米聚团流态化技术。     

Durable electrochromic coatings prepared from electronically conductive poly(3HT-co-3TPP)-silica hybrid materials

In this paper, a series of organic-inorganic hybrid materials, consisting of heterocyclic conjugated poly(3-hexylthiophene), P3HT, network, and silica particles, were successfully prepared for electrochromic studies. First, the heterocyclic co-polymer of poly[3-hexylthiophene-co-N-(3-trimethoxysilylpropyl) pyrrole], P(3HT-co-3TPP), containing trimethoxysilyl functional groups in the co-polymer backbone as the sol-gel precursor were prepared by conventional oxidative polymerization. Subsequently, P(3HT-co-3TPP)-silica hybrid sol-gel materials in the form of coatings were prepared by baking the microslides and ITO-coated electrodes that had been cast with homogeneous blending solutions containing co-polymer, acid-dopant, tetraethyl orthosilicate (TEOS), and a few drops of water. The microstructures of silica particles formed in the P(3HT-co-3TPP)-silica hybrid materials were investigated by transmission electron microscopy (TEM). The as-prepared hybrid coatings had improved adhesion capability on inorganic glass substrates relative to the pure P3HT on the basis of electrochemical cyclic voltammetric studies and Scotch tape test evaluations. During potential cycling, the film color of P(3HT-co-3TPP)-silica hybrid materials and P3HT coated on ITO electrode changed from orange yellow (i.e., reduced form) to dark blue (i.e., oxidized form) as the redox reactions proceeded. Effects of the material composition of P3HT along with hybrid materials on the electrochemistry, spectroelectrochemistry, thermal stability, and electrical conductivity were also studied.     

Room‐Temperature Tailoring of Vertical ZnO Nanoarchitecture Morphology for Efficient Hybrid Polymer Solar Cells

A ZnO nanoarchitecture, i.e., ZnO nanosheet (NS) framework, is demonstrated to be a promising electron acceptor and direct electron transport matrix for polymer‐inorganic hybrid solar cells. The ZnO NS framework is constructed on nanoneedles/indium tin oxide substrate via a room‐temperature chemical bath deposition (RT CBD). The framework morphology can be simply tailored by varying the concentration of precursor solution in the RT CBD. The ZnO nanoarchitecture with an appropriate free space between the NSs is consequently demonstrated to facilitate poly(3‐hexylthiophene) (P3HT) infiltration, resulting in superior interface properties, i.e., more efficient charge separation and less charge recombination, in the hybrid. Moreover, apart from the characteristics similar to the ZnO nanorod (NR) array, including vertical feature and single crystalline structure, the ZnO NS framework exhibits a slightly larger absorption edge and a faster electron transport rate. A notable efficiency of 0.88% is therefore attained in the ZnO NS‐P3HT hybrid solar cell, which is higher than that of the ZnO NR‐P3HT hybrid solar cell.     

Photothermally Sensitive Poly(N‐isopropylacrylamide)/Graphene Oxide Nanocomposite Hydrogels as Remote Light‐Controlled Liquid Microvalves

A photothermally sensitive poly(N‐isopropylacrylamide)/graphene oxide (PNIPAM/GO) nanocomposite hydrogel can be synthesized by in situ γ‐irradiation‐assisted polymerization of an aqueous solution of N‐isopropylacrylamide monomer in the presence of graphene oxide (GO). The colors and phase‐transition temperatures of the PNIPAM/GO hydrogels change with different GO doping levels. Due to the high optical absorbance of the GO, the nanocomposite hydrogel shows excellent photothermal properties, where its phase transitions can be controlled remotely by near‐infrared (NIR) laser irradiation, and it is completely reversible via laser exposure or non‐exposure. With a higher GO loading, the NIR‐induced temperature of the nanocomposite hydrogel increases more quickly than with a lower doping level and the temperature can be tuned effectively by the irradiation time. The nanocomposite hydrogel with its excellent photothermal properties will have great applications in the biomedical field, especially as microfluidic devices; this has been demonstrated in our experiments by way of remote microvalves to control fluidic flow. Such an “easy” and “clean” synthetic procedure initiated by γ‐irradiation can be extended for the efficient synthesis of other nanocomposite materials.     

可溶性聚吡咯甲烯衍生物的光电性能研究

在酸性条件下制备可溶性聚{(3-丙酰基)吡咯-[2,5-二(对硝基苯甲烯)]}(PPPDNBE),并且对PPPDNBE的热稳定性能、光物理性能和电化学性能进行研究.热失重曲线显示,PPPDNBE的初始分解温度为187.41℃.紫外-可见吸收光谱表明,PPPDNBE溶液和薄膜的共轭吸收峰分别位于476 nm和484 nm.PPPDNBE为橙色发光材料,最大发射波长为612 nm.PPPDNBE的光学带隙和电化学带隙分别为1.68 eV和1.62 ev.此外,PPPDNBE还可以用作电容器的阴极材料,随着电压扫描速率增加,储存的电量逐渐增大.     

Effect of the fabrication method on the electrical properties of poly(acrylonitrile-co-butadiene-co-styrene)/carbon black composites

Poly(acrylonitrile-co-butadiene-co-styrene) (ABS), an engineering plastic, was combined with carbon black (CB) to increase its conductivity. The ABS/CB composites were prepared using two different methods: dissolution of ABS in Butan-2-one and manual mixing of the constituent materials. These fabrication methods led to different microstructures, which led to vastly different electrical properties. The microstructures were acquired using scanning electron microscopy (SEM) and optical microscopy, while the electrical conductivity was obtained using impedance spectroscopy. The percolation threshold of the composites fabricated using the manual mixing method was found to be much lower (0.0054 vol.% CB) than that of the composites fabricated using the dissolution method (2.7 vol.% CB).     

0.8μm多晶栅等离子刻蚀研究

文章基于Mintab软件,运用Precision 5000等离子刻蚀技术研究0.8μm多晶栅刻蚀中功率、压力、HBr流量、Cl2流量对刻蚀效果的影响。获得了四个因素对刻蚀效果影响的主次关系,同时由Mintab软件分析获得了各因子效应的pareto图,各因素对多晶条倾斜角度影响的主效应图,各因子对刻蚀效果的正态分布图,并拟合获得了多晶栅刻蚀的最优化条件。运用最优化条件刻蚀多晶栅,其结果表明剖面倾斜角度及表面形貌均能达到MOS器件的工艺制造要求。     

Self‐Crosslink Method for a Straightforward Synthesis of Poly(Vinyl Alcohol)‐Based Aerogel Assisted by Carbon Nanotube

As a new concept, a self‐crosslink mechanism for hydrothermal synthesis of poly(vinyl alcohol) (PVA) aerogel, assisted by multiwall carbon nanotubes, is reported. PVA, working as a low‐cost and commercially available raw material, exempts the complicated synthesis process and reserves its nontoxic nature since no organic crosslinkers are used in the synthesis process. The crosslink density and many other properties of the products can be easily tuned by simply altering the concentration of PVA precursors, which is considered to be another feature of our method. Dehydration between hydroxyl groups occurs in the hydrothermal process, leading to a reverse wettability of the products from hydrophilic to hydrophobic, thus their absorbing capacity for several organic solvents, such as bean oil and crude oil, is investigated. The absorbate has 10–52 times the original weight of the aerogel. As exhibited by the cytotoxic tests, the product has neglectable toxicity, suitable for application in environmental bioengineering. Furthermore, the product can be used as a facile substrate for transformation into conductive aerogel by in situ hybridizing with polypyrrole, showing a conductivity of 0.16 S m^?1. As it is rich in hydroxyl groups, the aerogels are believed to be further functionalized by the reactions related to the hydroxyl group.     

Thermoresponsive Hydrogels as Microniches for Growth and Controlled Release of Induced Pluripotent Stem Cells

The recently emerging stem-cell artificial niche engineering in induced pluripotent stem cell (iPSCs) 3D cultures has provided enormous opportunities to fully utilize the potential of these cells in biomedical applications. Although a fully chemically defined niche environment can supply cells with desirable safety for clinical use, establishing an artificial degradable niche environment for the controlled release of proliferated cells under mild conditions is still a big challenge. Here, an advanced controlled releasable iPSC 3D artificial niche is reported based on dendritic polyglycerol and poly(N-isopropylacrylamide)-co-polyethylene glycol polymers via a physical–chemical cogelation strategy. Benefiting from the chemically defined synthetic materials and their precise cooperation by covalent cross-linking and physical phase transition, the cogelation-based artificial niche system can be adjusted with optimal parameters and owns high cell biocompatibility to support the robust production of high quality iPSCs with an excellent expansion efficiency. Moreover, the expanded cells can be released out of their niche environment controllably only by adjusting the temperature. Overall, this controlled release hydrogel scaffold shows great promise in iPSC 3D culture for downstream applications.     

一种采用斩波稳零技术的16位,96kHz带宽Σ-Δ AD转换器

介绍了一个16位精度Σ-Δ型模拟数字转换器.它由一个模拟的调制器和一个数字降采样滤波器组成.调制器采用了传统的单环两阶的结构,在第一阶调制器中采用了斩波稳零技术来消除电路的闪烁噪声.数字的降采样器包括多相梳状滤波器和波数字滤波器,功耗低,面积小.实验结果表明转换器获得了92dB的动态范围和96kHz的带宽.整个芯片由0.18μm六层金属CMOS工艺制造,芯片面积为2.68mm2,功率消耗仅为15.5mW.