含磺化聚苯胺和重氮树脂自组装超薄膜的制备及其光电转换性能

具有共轭结构的高分子化合物正日益被人们所重视 ,并被应用于导电、光电、电致发光等方面的研究 [1～ 3] .聚合物较之传统的无机太阳能材料 (如硅半导体等 )具有价格低廉 ,可方便地改变结构等优点 ,其光电转换性能的研究主要集中在提高光电转化效率和可加工性能 [4 ,5]两个方面 .由于共轭高分子如聚苯胺在一般溶剂中的溶解性较差 ,人们通过合成取代聚苯胺来提高其溶解性 ,从而改善其加工性能 ,为最终提高其在功能器件中的应用提供保证 .磺化聚苯胺就是通过在苯环上引入磺酸基而使其成为一种水溶性的高聚物 .自组装技术自 1 991年由 Decher[…     

The History and the Current Revival of the Oxo Chemistry of Iron in its Highest Oxidation States: FeVI – FeVIII

The history of the oxo compounds of iron in its highest oxidation states is reviewed and modern activities in this long neglected area of inorganic chemistry are highlighted. The chemistry of ferrates(VI) is the most rapidly advancing branch owing to several potential applications in diverse fields such as environmental chemistry and energy storage. Convenient and high‐yield preparations of ferrates(VI) in high purity are presented, followed by a coverage of the analytical, spectroscopic, and structural characterization in the solid and in solution, with a focus on the stability of these compounds, which had long been under‐estimated. Particular attention has been paid to the fascinating mechanisms that have been proposed for the intriguing “self‐decay” of the [FeO₄]^2– dianion. Redox processes with inorganic and organic substrates are summarized including fresh and waste water treatment on the one hand and “super‐iron batteries” on the other. Recent advances in the experimental and computational approach to ferrates(VII) [FeO₄]^– and the elusive “iron tetroxide” [FeO₄] are described.     

Confinement of the infrared divergence for the Mumford process

The Mumford process X is a stochastic distribution modulo constant and cannot be defined as a stochastic distribution invariant in law by dilations. We present two expansions of X—using wavelet bases—in X=X₀+X₁ which allow us to confine the divergence on the “small term” X₁ and which respect the invariance in law by dyadic dilations of the process.     

Two new polyoxovanadate clusters templated through cysteamine

Two new fully oxidized polyoxovanadate cluster-based solids (C₄N₂S₂H₁₄)₂[H₂V₁₀O₂₈]·4H₂O,1 and (C₄N₂S₂H₁₄)₅[H₄V₁₅O₄₂]₂·l0H₂O,2 are crystallized under self-assembly process in the presence of cysteamine. In both1 and2, cysteamines are oxidized forming disulphide linkages and occur as counter cations. The organic cations assemble around V₁₀O₂₈ cluster anions in1 whereas they aggregate around V₁₅O₄₂ clusters in 2· pH appears to be the structure determinant in the occurrence of decavanadate cluster in1 and pentadecavanadate in2, with the same counter cation.     

Electrochemical STM investigation of 1,8-octanedithiol monolayers on Au(1 1 1).: Experimental and theoretical study

The surface structure of Au(1 1 1) electrodes covered by 1,8-octanedithiol self-assembled monolayers (SAMs) was studied with in situ scanning tunnelling microscopy (STM) as a function of the electrode potential in acidic and alkaline electrolytes. We investigated the correlation between the dynamics of the SAM and the underlying gold atoms during the reductive desorption and oxidative readsorption processes. The reductive desorption of 1,8-octanedithiol is characterized by a transition from a compact monolayer with an upright molecular configuration to a striped phase with flat lying dithiol molecules, whereas during the oxidative readsorption process the surface first becomes increasingly covered by the striped phase until the transition to the compact phase occurs. We also considered under equivalent conditions 1-octanethiol/Au(1 1 1) SAMs which were used as a reference to evaluate the influence of the -SH terminal group on the structure and stability of dithiol SAMs. The desorption and readsorption of both the dithiol and the monothiol have a considerable influence on the substrate morphology which is manifested in the dynamics of vacancy islands, gold islands and indentation of step edges. Quantum mechanical calculations in the framework of density functional theory (DFT) show that adsorbed thiols greatly facilitate the detachment of gold atoms from step edges. The high mobility of gold atoms observed experimentally is compatible with the presence of a defected layer of gold atoms. The DFT results suggest that the formation of a monolayer may involve the diffusion and self assembly of thiolate-Au moieties rather than the diffusion of the bare thiolates across the surface. This mechanism explains the formation of a defected layer of gold atoms.     

Normal incidence X-ray standing wave analysis of thin gold films

Normal incidence X-ray standing wave (NIXSW) analysis has been successfully performed on epitaxial gold films on mica substrates using reflection from the (1 1 1) planes parallel to the surface. We show that NIXSW can be used to monitor the decrease in order within the gold film caused by annealing, and the position of sulfur within a monolayer of methyl thiolate (CH₃S-) on the surface. The Au-S layer spacing was found to be 2.54 ± 0.05 Å, in close agreement with previous work on a single crystal system.     

Surface strain due to embedded epitaxial islands

We present a simple methodology for the evaluation of strain on the free surface above an embedded island. This work is motivated by the technological importance of self-organization of nanostructures. We first obtain the exact solution of the problem of a particle embedded in a half-space, using continuum theory. Then, we obtain a simple mathematical expression for the strain on the surface. In order to account for the influence of surface energy at the nanoscale, surface and interface stress are considered through the continuum Gurtin formulation. The results are compared with the classical approach, which typically ignores surface stress. This comparison illustrates a very dramatic (even qualitative) difference from the classical elasticity based prediction. It proves that surface stress must be taken into account when islands are small and softer than the substrate material. The procedure illustrated here should be useful to those who need usable expressions for surface strain and have no interest in solving the corresponding boundary value problem.     

“浮萍”与“倒浮萍”聚合物超薄膜结构与功能组装

总结了本实验室近年来在“浮萍”与“倒浮萍”聚合物超薄膜方面的研究工作，探讨了从分子构筑到功能组装的途径     

荧光探针法研究胶原蛋白的水溶液聚集状态

利用一种分子内电荷转移化合物３ 甲氧基 ４’ Ｎ，Ｎ 二甲氨基黄酮（ＤＭＭＦ）作为荧光探针，研究了胶原蛋白在水溶液中的聚集状态．研究结果发现，当胶原蛋白浓度增大到０５ｍｇ／ｍＬ以上时，ＤＭＭＦ在４６５ｎｍ处的荧光强度有一突跃；继续增大其浓度，荧光强度越来越大．证明胶原蛋白在水溶液中随浓度增大有明显的聚集行为．利用荧光偏振法测量该体系内ＤＭＭＦ的荧光偏振特性，发现当胶原蛋白浓度增大到０５ｍｇ／ｍＬ以上时，体系具有较高的微粘度，进一步证实了胶原蛋白在水溶液中的聚集特性．     

嵌段共聚物自组装及其在纳米材料制备中的应用(下)

嵌段共聚物可以自组装形成丰富的有序微结构。这些微结构可以拥有各种不同的几何形态和晶体／准晶结构及宽泛的尺寸选择性，而且具有良好的可调控性及相对容量的加工方法。利用嵌段共聚物这种自组装特性来制备一些利用传统技术难以获得的纳米材料（如功能纳米材料，纳米结构材料，模板材料，介孔固体等）及微米／亚微米微结构材料（如光子晶体等），具有优越性。这些材料将在信息技术，生物医学，催化等领域取得应用。