氧化锌-银复合纳米粒子的制备：吸收光谱和荧光光谱

金属和半导体纳米粒子的制备及性质的研究是当今材料科学和物理化学的热门课题［1－6］．在利用太阳能光降解环境污染物、生物传感器以及光生物等方面这些纳米粒子都具有实际应用的可能性．对纳米粒子表面进行修饰而形成的复合纳米粒子可以有效地调整单一颗粒的表面性质甚至颗粒的稳定性．另外，复合纳米粒子的制备对研究纳米粒子的尺寸量子化效应、非线性光学性质及其它光电性质都有重要的意义．人们已成功地制备了许多复合金属－金属纳米粒子，如Cu－Ag［7］，Ag-Pd［8］及Ag－Pt［9］等．关于复合半导体－半导作纳米粒子也有报导，如C…     

二氧化钛超薄膜的组装

近年来LB膜技术和超微粒子研究的发展，将两者有效地结合起来组装了与量子电子学、非线性光学、光电化学、化学生物传感器有关的纳米量级无机半导体材料［‘－‘j．其中TIO。纳米薄膜材料已在太阳能电池反射膜、压电铁电薄膜、电致显示器件［‘j、可逆光电池和超导薄膜［’］研究中都显示了广阔的应用前景．这类薄膜制备多采用化学气相沉积（CVD）技术和原子层外延．也有人把LB技术应用于纳米粒子的组装来制备TIO。超薄膜［”’j二本文利用烷氧基钛在水／空气界面上发生的溶胶一凝胶化反应制备TIO。基胶态粒子及其固态凝聚膜，将其与…     

乳状液法制备憎液溶胶Ⅰ.BaCO_3均匀粒子的制备

均匀胶体粒子的形成，除与反应条件（反应物浓度、陈化时间和温度、介质种类等）有关外，反应体系的环境也影响最终产物的形态，《至结晶结构．气溶胶法和微乳液法正是利用微环境中的‘水池效应”；分别制备出球形亚微米和纳米级的均匀粒子［‘－‘］、这些方法与水解法和相转化法等方法比较，反应物浓度要大几个数量级，而反应时间却短很多，因而受到研究人员的关注．乳状液也能提供亚微米、微米及以上级的微环境，因此，可以应用O／W乳状液乳液中的聚合反应制备亲液的分散体系．然而，极少有关利用w／O乳状液制备僧液溶胶的报导问；最近…     

PEO-PS共聚微粒在MgSO4溶液中聚集的分形

可溶性高聚物的聚集动力学研究在物理、化学、生物和医学工程等诸多领域都极有理论和实际应用价值，这方面的工作国外多有报导［‘，’，“］．最近Napper与他的合作者Zhu又报导用聚地异丙基丙烯酸胺（PNIPAM）空间稳定的聚苯乙烯（PS）微乳粒子在NaNO。中的聚集动力学研究［‘’］．指出该粒子的聚集生长遵循指数规律，聚集速率和描述生长过程的分形值（fractal山mension）随着NaNO。的浓度和温度增加·在所研究的条件范围内粒子的聚集过程属扩散限制型簇聚集（dffesion－h。tedclusteraggregation，DLCA．本文将报导用不同摩to＄…     

O／W微乳液中聚邻甲苯胺超微粒子的制备

聚邻甲苯胺具有较高的电导率、较好的贮存电荷的能力和良好的环境稳定性，因而具有较大的应用价值［’－‘j，其合成方法主要有电化学合成法和化学合成法［‘·’J．化学会成法所得聚邻甲苯肢的粒子一般大于100urn．近年来，以表面活性剂聚集体微乳液、溶致液晶为介质，制备超微粒子材料已为人们所关注「’－’］．以微乳液为介质进行聚合反应亦引起重视，但大部分微乳液聚合都是在四组分微乳液（表面活性剂、助表面活性剂、单体和水）中进行‘”·“‘．近年来，某些油溶性单体已成功地在无助表面活性剂的三组分微乳液中聚合［‘’·‘’1…     

微波水解法制备均分散α—Fe2O3纳米粒子的初步研究

微波水解法制备均分散α－Ｆｅ２Ｏ３纳米粒子的初步研究＊汤勇铮（皖南医学院生化组芜湖２４１００１）张文敏＊＊（安徽师范大学化学系芜湖２４１０００）关键词微波辐照水解氧化铁中图分类号Ｏ６１４．８１１均分散氧化铁胶体粒子有着广泛的应用［１］，可以用作制备催...     

γ-射线辐照法制备纳米Cu-Pd合金粉末的影响因素

纳米Ｃｕ－Ｐｄ合金粉末在催化［１－４］、电导体［１,５,６］、导电胶［１,６］、传感器［７］、气体吸附与分离［８,９］等许多方面有着重要用途。其制备方法虽较多［１－４,１１－１７］,但多数方法制备温度较高,难以制得纳米Ｃｕ－Ｐｄ合金。γ－射线辐照还原...     

表面改性的纳米氧化锌的制备及其吸收特性

自从８０年代Ｍａｊｉｅｖｉｅ的单分散超微粒合成技术取得成功以来［１,２］,制备单分散、不团聚的纳米材料一直是热门课题．纳米粒子的团聚会给制备、稳定化贮存及再复合时的均匀分散和高密度素胚的形成带来极大的困难［３］．本文报导了用超声微乳液法制备表面改性的单分散纳米氧化锌的条件,并对其光吸收特性研究时发现,不同的表面活性剂包覆会改变纳米材料的光吸收特性．１实验部分１．１纳米氧化锌的制备 将环己烷、醋酸丁酯及反应物水溶液分别用０．４５μｍ的超滤膜过滤,得到纯化试剂． １）将 ０． ２－０． ５ ｍＬ的 ０． ５…     

大粒径单分散金纳米粒子的水相合成

近年来,随着纳米科技的兴起,纳米尺度的金颗粒以其独特的光学、电学性质［１-３］在许多领域表现出潜在的应用价值,引起了人们浓厚的研究兴趣［４-７］．迄今为止,已有多种制备金纳米粒子的方法见诸报导．制备简便、单分散性好、粒径可控,一直是各种方法追求的目标．...     

TiO2-Al2O3作为Mo催化剂担体的研究

Tio。－AI。oa二元氧化物的制备at艺大体可分为两种．一种是利用液相浸渍或气相沉积方法将Tio。担载在AI。0。上，使Tio。主要覆盖在AI。0。表面上［‘－1另一种是通过Ti盐和AI盐混合溶液共沉淀方法使Tio。和AI。0。均匀混合在一起【‘－’1．不同的制备工艺对Tio。－AI。03的表面结构和表面性质有很大影响问．我们曾报导用TICly蒸气化学气相沉积方法制备出了D02在1川2O3表面呈现十分均匀分布的DoZ一周。03复合氧化物担体＊’1．本文进一步考察D0。在周。0。表面的沉积对川。0。孔结构的影响，以及Ti02－A1203作为加氢精制MO催…     

表面活性剂对制备MoO2纳米微粉的影响

Using polyvinyl alcohol(PVA)and sodium dodecyl sulfate(SDS)as the surfactants respectively,nano-size amorphous molybdenum dioxide powders were prepared by γ-radiation method at ambient pressure and room temperature,and the products were characterized by use of laser Raman spectra(LRS)、 X-ray powder diffraction(XRD)and transmisson electron micrograph(TEM).The experimental results reveal that the relative pure samples can be obtained using PVA as surfactant,and the average particle size is about 10nm,but using SDS as surfactant,the samples with the average particle size 30nm are a mixture of MoO2 and MoO3.This suggestes PVA is prior to SDS in the preparation of nano-sized amorphous molybdenum dioxide powders by γ-radiation method.     

The production of high polymer to surfactant microlatexes

Starved‐feed microemulsion polymerization of styrene was investigated. The influence of the type (SDS or Dowfax 2A1) and concentration of anionic surfactant on the final particle size of latex made by the polymerization of microemulsions of styrene was studied. In addition, the influence of 1‐pentanol and acrylic acid as cosurfactants was examined. Latexes with 20% solids content and polymer to surfactant ratio of 22 were produced, with a particle diameter of 42 nm and very low polydispersity indexes. Smaller particles are produced using SDS than Dowfax 2A1 for the same weight fraction of surfactant; however, similar particle sizes were obtained with the same molar concentrations of SDS and Dowfax 2A1. Further shot additions of monomer increased solids level as high as 40% and polymer to surfactant ratios greater than 40, with particles remaining monodisperse with average diameter smaller than 60 nm. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 48–54, 2010     

Synthesis and morphology of Ba(Zr<Subscript>0.20</Subscript>Ti<Subscript>0.80</Subscript>)O<Subscript>3</Subscript> powders obtained by sol–gel method

Barium zirconate titanate, Ba(Zr_0.20Ti_0.80)O₃ (BZT) powders were prepared by sol–gel method. These powders were characterized by thermogravimetric and differential thermogravimetric analyses (TG-DTA), X-ray diffraction (XRD) and microcopy electron transmission (TEM). The decomposition of the precursors was monitored by TG-DTA. XRD patterns reveal that BZT powders heat treated at 800 °C present single phase with perovskite-type cubic structure. TEM micrographs were employed to estimate the average particle size of the BZT powders (≈ 20 nm). The results indicate that the particle size of the BZT powders increases with the increasing of the holding time and aging temperature. The low aging temperature can reduce the agglomeration of the nanopowders. Three polyalcohols were employed as surfactants in sol–gel method: butanol (BTOL), polyethylene glycol (PEG) and polyvinyl alcohol (PVA). It is noted that PEG has a better effect on reducing agglomeration of BZT powders than that of the BTOL and PVA.     

Influences of surfactant (PVA) concentration and pH on the preparation of copper nanoparticles by electron beam irradiation

Electron beam irradiation method was successfully applied to the preparation of Cu nanoparticles in aqueous solution under room temperature and ambient pressure using polyvinyl alcohol (PVA) as the surfactant. The influences of the pH on the products were studied by X-ray diffraction (XRD), and those of the surfactant PVA concentration on the particle size and agglomeration by ultraviolet–visible spectrophotometry (UV–vis) and laser scattering particle size distribution analysis (LSPSDA). The products were characterized by XRD and transmission electron microscopy (TEM). The results showed that the grain size of Cu nanoparticles, within a certain range, can decrease with increasing PVA concentration. Pure Cu nanoparticles with the grain size distribution of 5–50 nm were prepared when the pH was adjusted between 5.0 and 9.0, and the PVA concentration was 2.20 g/100 mL.     

喷雾-胶凝法制备超细莫来石粉末

以水玻璃和硝酸铝为原料 ,通过喷雾 -胶凝法和共沸蒸馏技术制备莫来石前驱粉体 ,然后煅烧得到超细莫来石粉末 .用TG -DTA、XRD、TEM及BET研究了莫来石前驱粉体在煅烧过程中的热学性质、物相与比表面变化及颗粒大小与形貌变化 ,并对所制得的莫来石粉进行了表征 .结果表明 ,莫来石前驱粉体经 130 0℃煅烧 1h可制得粒径为 2 5nm～ 4 0nm ,比表面积为 4 2 5m2 /g的莫来石超细粉 ;煅烧过程中的物相变化次序为 :勃姆石 +非晶态SiO2 →非晶态Al2 O3 +非晶态SiO2 →γ -Al2 O3 +非晶态SiO2 → 3Al2 O3 ·2SiO2 .     

以次磷酸镍为原料制备NiP和NiPB非晶态合金的新方法

以次磷酸镍为原料用化学还原法制备出了NiP和NiPB非晶态合金.用ICP、XRD和TEM等方法对催化剂物性进行了表征.研究了制备条件，如原料浓度、温度、pH值及引发剂的加入对制备NiP非晶态合金的影响.在300 K下所制备的NiP非晶态合金平均粒径约为30 nm.研究了原料浓度与原料配比对NiPB非晶态合金物性的影响，可通过改变原料浓度和配比得到所需组成的NiPB非晶态合金. NiPB非晶合金平均粒径约为15 nm.     

The Effect of a Magnetic Field on a RAPET (Reaction under Autogenic Pressure at Elevated Temperature) of MoO(OMe)(4): Fabrication of MoO(2) Nanoparticles Coated with Carbon or Separated MoO(2) and Carbon Particles

In this article, we present results of the RAPET dissociation of MoO(OMe)4 at 700 degrees C in a closed Swagelok cell. The reaction produces molybdenum dioxide nanoparticles (20 nm) coated with carbon (20 nm). We have also carried out the same reaction under an applied magnetic field of 10 T. This reaction yielded different products. It produces a mixture of comparatively larger (50 nm) molybdenum dioxide nanoparticles and separated uncoated carbon particles (20-30 nm).     

Kinetic aspects of styrene minisuspension polymerization using a mixture PVA-SDS as stabilizer: Effect of the time of addition of SDS

The styrene minisuspension polymerization at 70 °C using AIBN as initiator and Polyvinil alcohol (PVA) and mixture PVA-sodium dodecil sulfate (SDS) as stabilizers was studied focusing on the kinetic behavior of the process after the SDS was added (PVA is present from the beginning and SDS is added at a given time t_SDS). It was confirmed that the addition of SDS to the system initially stabilized with PVA highly enhances the colloidal stability of the polymer particles because of the association formed between SDS and PVA molecules. It was observed that when SDS is added the rate of polymerization, the average molecular weight and final latex viscosity increase. The earlier the addition of SDS the more marked these increments. This behavior is explained in terms of the colloidal stability of the particles formed via emulsion polymerization and its effect on kinetic aspects such as the evolution of molecular weight and particle size distributions during the minisuspension polymerization.     

氧化-还原低温引发甲基丙烯酸甲酯/丙烯酸丁酯超浓乳液聚合研究

以乳化剂十二烷基硫酸钠 (SDS)和共乳化剂十六烷醇 (HD)作为复合乳化体系 ,过氧化二苯甲酰(BPO)和N ,N 二甲基苯胺 (DMA)作为氧化还原引发体系 ,甲基丙烯酸甲酯 丙烯酸丁酯 (MMA BA)作为混合单体 ,制备了分散相占 83 %以上的稳定的超浓乳液 ,然后在低温下引发聚合 .探讨了引发剂浓度、氧化剂与还原剂的摩尔比、乳化剂的浓度、液膜增强剂的种类、聚合温度等因素对聚合稳定性和聚合速率的影响 ,测定并计算得到了聚合速率的公式 ;用激光散射粒度分布仪测定了聚合物乳胶粒子的大小及粒径分布 ,用透射电子显微镜观察了聚合物乳胶粒的形态 ,讨论了乳化剂浓度、聚合温度等对乳胶粒形态、大小的影响     

Novel multilamellar mesostructured molybdenum oxide nanofibers and nanobelts: synthesis and characterization

One-dimensional molybdenum oxide nanostructures with layered mesostructures were prepared directly from commercial bulk MoO3 crystals by a surfactant-templated hydrothermal process. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectra, and thermal analyses have been used to characterize the obtained molybdenum oxide nanomaterials. By use of cetyltrimethylammonium bromide as the structure-directing template, novel molybdenum oxide nanofibers with triple interlayer distances of 2.84, 2.66, and 2.46 nm have been obtained. The nanofibers have diameters of 20-100 nm and length up to 20 microm. The growth of multilamellar molybdenum oxide nanofibers can be interpreted by the combination of surfactant/inorganic self-assembly process and host/guest intercalation chemistry. On the basis of the X-ray diffraction and infrared results, a possible arrangement of surfactant in the interlayer space of molybdenum oxide by bilayer micelles with different tilt angles has been proposed. In addition, the thermal stability of surfactant has been improved by intercalation. Moreover, molybdenum oxide nanobelts with two kinds of interlayered structures were also produced in the presence of n-alkylamines (n = 12, 14, 16, and 18) following a similar method, these nanobelts show length up to more than 10 microm, width ranging between 200 and 600 microm, and width-to-thickness ratios of about 3-12. A linear relationship is observed between the interlayer distance and the number of carbon atoms in n-alkyl chains.