分子动力学方法研究纳米摩擦问题

分子动力学方法中忽略了电子相互作用,因而具有高效率,可以从原子水平研究大体系的动态过程。随着计算技术的进步,分子动力学逐渐在纳米工程领域显现了巨大的应用前景。本文综述了利用分子动力学方法从微观角度研究摩擦行为的进展,同时也就其进一步的应用做了展望。     

紫外-可见分光光度法测定电镀液中纳米Al2O3含量的研究

采用紫外-可见分光光度法测定纳米Al2O3电镀液中(四种不同电镀液)纳米微粒的含量。研究表明，这些体系均存在空白液吸光度很低、工作液吸光度较高的较宽的波长区间，是光度分析法中理想的测定体系，标准曲线的相关系数均大于0．98，其平均相对误差(2．93％)远远小于重量分析法(20．7％)。     

从零维到三维的金范式: 金单质概念的新发展

含有零维金纳米球的胶体金,在古埃及就已经被用于制造彩色玻璃,但直到20世纪,人们才对其进行系统的研究。20世纪下半叶,一维金纳米棒的合成及其奇异的光学性质引起了科学家对金纳米颗粒的关注。随后,二维金纳米片、三维金纳米哑铃等金纳米颗粒的相继出现,丰富和发展了金单质的概念。几种新的金单质的发现,构建了从零维到三维的金范式,从而启发人们对“金单质”及其应用进行更加深入的探究。     

PMMA/PS纳米复合材料的制备及分散相稳定性研究

纳米复合材料具有许多优异的性能，但是由于纳米粒子常常很难以纳米尺寸均匀地分散在基体中，有时即使实现了纳米级分散，在后加工或应用过程中又会发生二次团聚，使得纳米材料的特性不能充分发挥．因此，要获得性能优异的纳米复合材料首先必须解决纳米材料在基体中的均匀、稳定分散问题．     

第2届国际电化学会(ISE)春季会议纪要

第2届国际电化学会(ISE)春季会议于2004年3月7日至10日在厦门大学召开,会议由厦门大学固体表面物理化学国家重点实验室主办,田中群教授担任会议主席,本次会议主题为“纳米尺度上的电化学-构筑、表征、理论”,主要包括以下三方面内容：(1)运用电化学新方     

纳米通道内表面浸润性对气泡的作用

运用分子动力学模拟方法研究了在质量力驱动下不同浸润性壁面纳米通道中气泡的分布及其运动状况, 提出了一种统计纳米通道中气泡运动速度的方法. 结果显示, 在亲水性壁面的纳米通道中, 气泡位于通道中间, 气泡的运动速度接近但小于通道中心流速, 在势能强度较大时, 壁面吸附的分子较多, 气泡也较大, 反之则气泡较小; 对超疏水性壁面, 气泡则位于固壁附近, 两个壁面形成对称的一对气泡, 气泡的运动速度接近但大于边缘速度. 流体总的流动速度随着流体粒子与壁面粒子作用的减弱而增大, 滑移速度则逐渐从负转变为正.     

纳米金属铜与纳米氧化锌之间相互作用的EPR和XPS研究

由于纳米材料独特的表面效应、电子效应及量子尺寸效应 ,已被广泛应用于各个领域 .有关纳米材料研究的报道很多 [1～ 7] ,大部分是关于纳米材料的制备[1～ 4 ] 及其特性研究 .对于纳米金属及纳米氧化物之间相互作用的研究迄今尚未见报道 .本文采用超声分散和机械研磨法物理混合纳米金属铜粉和纳米氧化锌 ,借助 EPR和 XPS技术对样品进行了表征 ,发现混合体系出现了 Cu2 + 的顺磁信号 ,Zn L3M4 5M4 5俄歇动能和 O1s的电子结合能亦发生了变化 ,表明纳米 Cu0 和纳米 Zn O之间存在相互作用 ,作用形式为 Cu— O—Zn.1　实验部分1 .1　样品…     

PANI/Ce(OH)3-Pr2O3·3H2O/NanoG复合材料制备与表征

开发了反胶束模板-原位聚合纳米复合法制备聚苯胺(PANI)/Ce(OH)3-Pr2O3·3H2O/石墨纳米薄片(NanoG)纳米复合材料的方法.膨胀石墨在乙醇水溶液中经超声处理制得石墨纳米薄片,以苯胺的氯仿溶液为油相,稀土金属离子Pr3+、Ce3+水溶液为水相,依靠表面活性剂十六烷基三甲基溴化铵(CTAB)自组装形成的反胶束为模板-制备PANI/Ge(OH)3-Pr2O3·3H2O/NanoG复合材料.利用红外光谱(FTIR)、扫描电镜(SEM)、透射电镜(TEM)和 X-射线衍射(XRD)对该复合材料进行了表征和分析,研究了其导电性能和热性能.结果表明,PANI/Ce(OH)3-Pr2O3·3H2O/NanoG复合材料各相分散均匀,稀土纳米粒子在体系中以棒状的形态分布.热重分析表明,该复合材料的热稳定性明显提高;导电性研究说明,石墨纳米薄片的特殊的结构(较大的径厚比)对其在聚合物基体中形成导电网络具有重要作用;PANI/Pr2O3-Ce(OH)3/NanoG纳米复合材料的渗滤阀值低于1.0wt%.     

PANI／Ce（OH）3-Pr2O3·3H2O／NanoG复合材料制备与表征

开发了反胶束模板-原位聚合纳米复合法制备聚苯胺（PANI）／Ce（OH）3-Pr2O3·3H2O／石墨纳米薄片（NanoG）纳米复合材料的方法。膨胀石墨在乙醇水溶液中经超声处理制得石墨纳米薄片,以苯胺的氯仿溶液为油相,稀土金属离子Pr^3＋、Ce^3＋水溶液为水相,依靠表面活性剂十六烷基三甲基溴化铵（CTAB）自组装形成的反胶束为模板。制备PANI／Ce（OH）3-Pr2O3·3H2O／NanoG复合材料。利用红外光谱（FTIR）、扫描电镜（SEM）、透射电镜（TEM）和X-射线衍射（XRD）对该复合材料进行了表征和分析,研究了其导电性能和热性能。结果表明,PANI／Ce（OH）3-Pr2O3·3H2O／NanoG复合材料各相分散均匀,稀土纳米粒子在体系中以棒状的形态分布。热重分析表明,该复合材料的热稳定性明显提高;导电性研究说明,石墨纳米薄片的特殊的结构（较大的径厚比）对其在聚合物基体中形成导电网络具有重要作用：PANI／Pr2O3-Ce（OH）3/NanoG纳米复合材料的渗滤阀值低于1.0wt％。     

纳米粒子在食源性致病菌检测中的应用进展

食品安全事关人民群众的身体健康和生命安全,而食源性致病菌是食品安全的主要影响因素。由食源性致病菌引起的疾病和死亡持续威胁着全球的公共卫生安全。因此,开发快速、准确且灵敏的食源性致病菌检测方法是预防食源性疾病暴发和确保食品安全的关键。常规检测方法费时费力,需要昂贵的设备和专业的人员,应用受限。近年来,随着纳米技术的快速发展,纳米粒子凭借其小尺寸、高比表面积和高反应活性等理化特性成为食源性致病菌检测领域的研究热点。此外,将识别元件修饰于纳米粒子表面并结合新颖的分析技术,能提高检测的特异性和灵敏度。该综述主要总结和比较了磁性纳米粒子、贵金属纳米粒子、荧光纳米粒子和二氧化硅纳米粒子在食源性致病菌检测中的应用,以期为食源性致病菌的快速分析提供思路。     

水溶性多壁碳纳米管/铜酞菁染料自组装薄膜的制备与表征

Water soluble multi-wall carbon nanotubes (MWCNTs) were prepared via chemical oxidation. Under ultrasonication,the chemically treated MWCNTs can be dispersed in water to form colloids. The MWCNTs were characterized by FT-IR spectra. The FT-IR spectra reveal the presence of carboxylic groups on the nanotubes. The functional groups can improve the nanotubes-solubility in water. Alcian Blue 8GX (AB), a quaternary ammonium dye of the copper phthalocyanine group, was dissolved in water and used to form electrostaticcally self-assembled multilayer films. The MWCNT/AB composite films were characterized by UV-vis absorption spectra as well as AFM and fluorescence spectrum. The experimental results show that the MWCNT/AB composite films can be produced easily. Compared to those of the AB aqueous solutions, composite films exhibit pronounced differences in the absorption and fluorescence spectra, which suggests that AB molecules aggregated in the composite film, and that a charge transfer might exist between AB molecules and the MWCNTs.     

Structural, photophysical, and photochemical characterization of 9-anthracenecarboxylate-hydrotalcite nanocomposites: evidence of a reversible light-driven reaction

ZnAl hydrotalcites containing increasing amounts of 9-anthracenecarboxylate anion (9AC) have been obtained via an anion-exchange procedure. In particular, intercalated and/or surface-exchanged samples were prepared to study the effect of the chromophore packing on their photophysical and photochemical behavior. Surface-exchanged samples were obtained by equilibrating the carbonate form of the ZnAl hydrotalcite with dilute solutions of 9AC. The nitrate form of the ZnAl hydrotalcite was instead chosen for the preparation of intercalation compounds. The maximum loading of 9AC was found to be 44% of the anion-exchange capacity. The obtained nanostructured materials were characterized by chemical and thermal analysis and X-ray powder diffractometry and studied for their photophysical and photochemical properties. The absorption and emission spectra of the materials revealed the formation of 9AC aggregates. The time-resolved fluorescence properties of the hybrid materials were investigated in bulk and under space-resolved conditions. The fluorescence decays appeared to be quite complex and were affected by the microenvironment and the experimental conditions. Generally, a shortening of the main fluorescence decay component was observed with increasing matrix loading, thus suggesting the occurrence of nonradiative processes in competition with fluorescence at high chromophore concentrations. Indeed, the occurrence of an electron-transfer process to water molecules, which led to the formation of 9AC radical, was observed spectrophotometrically in the sample with high 9AC loading. The electron-transfer process was completely reversible under air-equilibrated conditions.     

Free volume related fluorescent behavior in electron beam irradiated chalcone doped PVA

Effect of electron irradiation on the free volume related microstructural and optical properties of chalcone doped Poly(vinyl alcohol) composite films have been studied using FTIR, UV-Visible, XRD and Positron Annihilation techniques. The FTIR spectral study shows that the irradiation induces the crosslinking within the composite. Using UV-Visible absorption spectra the optical energy band gap and activation energies were estimated and the variation of these parameters suggests the existence of defects and molecular ordering within the irradiated composite. XRD diffractograms reveal that the crosslinking enhances the crystallinity of the sample. In this cross-linked polymer composite the fluorescence enhancement has been observed in the fluorescence spectral study. The Positron annihilation result suggests that the irradiation affects the free volume properties and crosslinking hinders the chalcone chromophore molecular rotation. Under this restricted condition the chromophore molecules likely to emit enhanced fluorescence and its mobility is directly related to the free volume around it.     

Synthesis,Spectroscopy, and Computational Analysis of Photoluminescent Bis(aminophenyl)‐Substituted Thiophene Derivatives

Substituted oligothiophenes have a long history in the field of organic electronics, as they often combine outstanding electro‐optical properties with the ease of synthesis. To assist the rational selection of the most promising structures to be synthesized, there is the demand for tools that allow prediction of the properties of the materials. In this study, we present strategies for synthesis and computational characterization, with respect to the fluorescence behavior of oligothiophene‐based materials for organoelectronic applications. In a combined approach, sophisticated computational methodologies are directly compared to experimental results. The M06‐2X functional in combination with the polarizable continuum model in a state‐specific formulation for excited‐state solvation proved to be particularly reliable. In addition, a semiclassical approach for describing the vibrational broadening of the spectra is employed. As a result, a robust procedure for the prediction of the fluorescence spectra of oligothiophene derivatives is presented.     

Preparation of Ce3+-Doped Inorganic-Organic Hybrid Materials Using Functionalized Silanes

Ce3+-doped, inorganic-organic hybrid monoliths were prepared from Si(OCH3)4, CH3 Si(OCH3)3, CeCl3 and various functionalized silanes (FSs) such as amino- (APTM), glycidyloxy- (GPTM), trifluoro- (TFTM) and chloro-(CPTM) silanes at 60°C by the sol-gel process. The functional groups of silane coupling agents coordinated with Ce3+ ions in the inorganic-organic materials. Ce3+-doped materials were transparent under the preparation conditions of FS/Ce3+ ratio of 100 and 1.0 × 10–4 mol/cm3 of Ce3+ concentration. Optical properties such as absorption spectra, emission spectra and fluorescence quantum yield for the Ce3+-doped hybrid materials were strongly affected by the Ce3+ ion environment. Emission spectra were observed for the Ce3+-doped materials below 400 nm. The emission intensities of the materials prepared from TFTM, CPTM and without FS were approximately 100 times as much as those of materials prepared from APTM and GPTM. The fluorescence quantum yield was highest (11%) for the material prepared from TFTM hybrid materials.     

用“超分子板块构筑法”制备有机/无机组装体发光材料

一般说来,高分子材料可以由小分子单体通过化学键结合而成[1],也可以通过非化学键的所谓超分子组装而成[2～4].后者是近年来高分子合成中十分活跃的领域.我们尝试将上述两种方法相结合来设计合成高分子功能材料,利用超分子化学法在设计功能性基团方面的便利性[2,5]和经典化学法在成键方面的有效性,提出了用"超分子结构单元"构筑高分子的方法.     

Surface modification of natural cellulose substances:toward functional materials and applications

Combining various synthetic chemical processes and biological assemblies provides a promising strategy for the design and fabrication of functional materials with tailored structures and properties.The unique multilevel structures and morphologies of natural cellulose substances such as ordinary commercial laboratory filter paper make them ideal platforms for the self-assemblies of various functional guest molecules that are to be deposited on the surfaces of their fine structures,and the resulting composite matters show significant potentials for various applications.The surface sol-gel process was employed to deposit ultrathin metal-oxide(e.g.,titania and zirconia)gel films to coat the cellulose nanofibers in bulk filter papers;thereafter,monolayers of specific guest substrates were immobilized onto the surfaces of the metal-oxide gel films.Highly selective,sensitive,and reversible chemosensors based on the surface modification of filter paper were obtained toward the fluorescence and colorimetric detection of various analytes such as heavy-metal ions,inorganic anions,amino acids,and gases.Cellulosebased composite materials with superhydrophobic,antibacterial,or luminescent properties were fabricated by self-assembly approaches toward practical applications.     

高分子化8-羟基喹啉锂的合成与静电自组装研究

设计合成了甲基丙烯酸二甲氨基乙酯(DM)含量为9.69%的丙烯酸甲酯共聚物(CPA),将制得的5-氯甲基-8-羟基喹啉(CHQ)挂接到CPA上,得到季铵型高分子化8-羟基喹啉(CPA-HQ)后,与金属离子Li+配位得到CPA-HQ-Li.化合物结构通过红外、紫外和荧光光谱等表征.多层超薄膜用CPA-HQ-Li和聚阴离子电解质(全氟磺酸)通过静电自组装制得.自组装膜的紫外和荧光相对于溶液(溶剂为四氢呋喃)发生了红移,膜的紫外吸收强度随组装膜层数增加线性增大,荧光强度随膜层数增加线性递减.高分子化8-羟基喹啉锂溶液和自组装膜的紫外和荧光光谱与文献报道一致.实验结果表明这种材料可用于有机电致发光器件(OLEDs)的制备.     

可聚合1,8-萘酰亚胺衍生物掺杂聚硅氧烷复合材料的合成及荧光特性

合成了3种可聚合的1,8-萘酰亚胺衍生物, 并研究了其在二甲基亚砜(DMSO)溶液中的光物理性质. 这些化合物表现出的光物理性质与其电子环境有关. 通过溶胶-凝胶法制备了可聚合1,8-萘酰亚胺衍生物与硅氧烷的共聚物. 尽管3种萘酰亚胺衍生物C-4位的取代基不同, 但在3-氨丙基三乙氧基硅烷(APTES)固凝胶中摩尔分数为0.06%时荧光强度均最大. 利用 ²⁹Si MAS NMR对合成材料进行了表征, 结果表明, 硅氧烷的缩聚程度影响材料的荧光强度, 说明材料中荧光单元的分子运动对材料的荧光性能有重要影响.     

以三亚吡嗪为中心的有机共轭分子的二阶NLO性质研究

采用密度泛函理论B3LYP/6-311G**方法,对一系列以三亚吡嗪为中心的有机共轭分子的二阶NLO性质和电子光谱进行了理论研究.结果表明,取代基推、拉电子能力的变化、相对数目及共轭桥的性质对研究分子的极化率及二阶NLO系数都有较大的影响.当研究分子以甲氨基为供体、以三氰基乙烯为受体、并以C=C双键为共轭桥时,显示了较大的二阶NLO活性和良好透光性的优化.该系列分子在NLO材料领域有较好的潜在应用价值.