固态组合化学及其在材料科学中的应用

概述了固态组合化学的概念及其在新材料开发中的应用 ,着重阐述了材料化合物薄膜库的组合制备方法和筛选技术的特点 ,简述了固态组合化学技术在超导、巨磁阻、磷光、催化剂、沸石等新材料开发中的应用以及固态组合化学现有技术中的困难和今后的发展方向     

High-throughput characterisation of materials by photoluminescence spectroscopy

An automatic system for high-throughput (HT) characterisation of large libraries of solid materials by photoluminescence spectroscopy is described. The system provides time-resolved transient emission spectra in the microsecond scale and can be employed for characterisation of materials of interest in the fields of catalysis and electroluminescence, amongst others. Here, we present its application to the optimisation of the ship-in-a-bottle synthesis of a novel electroluminescent polymer (PPV) and a photocatalyst (TP+), both encapsulated in large-pore zeolites.     

Thermal transporting properties of electrically conductive polyaniline films as organic thermoelectric materials

Thermal transporting properties of electrically conductive polyaniline films were first investigated in wide range of temperatures above room temperature as organic thermoelectric materials. Thermal conductivities of various protonic acid-doped polyaniline films were measured by combination of a laser flash method and a differential scanning calorimeter in relation with electrical conductivity and a kind of dopant. The thermal conductivities thus measured are in the range of conventional organic polymers, indicating that the doped polyaniline films have extremely low thermal conductivities among electrically conductive materials, and have correlation with neither electrical conductivity, nor a kind of dopant. Consequently the polyaniline film, which shows very high electrical conductivity, has comparable thermoelectric figure-of-merit (ZT) with feasible inorganic thermoelectric materials such as iron silicide. This revised version was published online in August 2006 with corrections to the Cover Date.     

A practical high-throughput screening system for enantioselectivity by using FTIR spectroscopy

For the first time FTIR spectroscopy has been applied to the measurement of enantiomeric purity. The underlying concept is based on the use of pseudo-enantiomers that are (13)C-labeled at appropriate positions. Upon applying Lambert-Beer's law in the determination of the concentrations of both enantiomers, the ee values are accessible, accuracy to within +/-5 % of the true values being possible. The application of a commercially available high-throughput FTIR system results in a slightly decreased accuracy (+/-7% for the ee values), but this allows a throughput of up to 10000 samples per day. The method is of interest in the area of combinatorial symmetric catalysis and directed evolution of enantioselective enzymes.     

ZnO纳米线基MWNTs/PVDF复合热电材料的制备及特性研究

将不同比例的多壁碳管(MWNTs)与聚偏二氟乙烯(PVDF)聚合物混合后,喷涂于n型ZnO半导体纳米线阵列上,制备了一种新型ZnO纳米线基MWNTs/PVDF热电复合材料.与以往采用价格昂贵的p型与n型单壁碳纳米管(SWNTs)与聚合物混合制备的复合热电材料特性相比,这种新型热电复合材料在降低制造成本的同时,利用分散于聚合物中MWNTs的一维电子传输特性及形成的大量界面势垒,加上ZnO半导体纳米线具有的较高载流子密度与迁移率,提高了复合热电材料中电子的输运特性,增加了材料对声子的散射强度.测试发现,在一定的温度梯度下,随着MWNTs添加质量百分比的增加,热电材料的温差电动势和电导率也随之增加,但其Seebeck系数变化量不大.研究表明,这种热电材料有望替代采用p型与n型SWNTs构建的SWNTs/PVDF复合热电材料.研究结果对开发超轻、无毒、廉价、可应用于各种微纳电子领域的新型电源具有重要的参考价值.     

Basic principles for rational design of high-performance nanostructured silicon-based thermoelectric materials

Recently, nanostructured silicon-based thermoelectric materials have drawn great attention owing to their excellent thermoelectric performance in the temperature range around 450 °C, which is eminently applicable for concentrated solar thermal technology. In this work, a unified nanothermodynamic model is developed to investigate the predominant factors that determine the lattice thermal conductivity of nanocrystalline, nanoporous, and nanostructured bulk Si. A systematic study shows that the thermoelectric performance of these materials can be substantially enhanced by the following three basic principles: 1) artificial manipulation and optimization of roughness with surface/interface patterning/engineering; 2) grain-size reduction with innovative fabrication techniques in a controllable fashion; and 3) optimization of material parameters, such as bulk solid-vapor transition entropy, bulk vibrational entropy, dimensionality, and porosity, to decrease the lattice thermal conductivity. These principles may be used to rationally design novel nanostructured Si-based thermoelectric materials for renewable energy applications.     

Facile measurement of polymer film thickness ranging from nanometer to micrometer scale using atomic force microscopy

As many properties of polymer thin films critically depend on their thickness, a convenient and cost‐effective method for precise measurement of film thickness in a wide range is highly desirable. Here, we present a method which enables polymer film thickness, ranging from nanometer to micrometer scale, to be facilely determined by measuring the height of an artificially created film step on smooth substrates with atomic force microscopy (AFM). Three polymeric films (polystyrene, poly(methyl methacrylate) and poly(styrene–ethylene/butylene–styrene) films), spin‐coated on either mica or quartz substrate with thickness ranging from 5.7 nm to 4.4 µm, were employed to demonstrate the procedure and feasibility of our method. The proposed method is particularly suitable for thicker polymer films, thus complementing the traditional AFM ‘tip‐scratch’ method which is generally limited to polymer films of no more than 100 nm thickness. Copyright © 2010 John Wiley & Sons, Ltd.     

Paper: An effective substrate for the enhancement of thermoelectric properties in PEDOT:PSS

A novel strategy via paper as an effective substrate has been introduced as a thermoelectric material in this work. Free‐standing poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/paper composite films are conveniently prepared by a one‐step method of directly writing PEDOT:PSS solution on paper, making the process simple, rapid, and facile. The free‐standing composite films display excellent flexibility, light weight, soaking stability in water, and great potential in large‐scale production. Improved thermoelectric properties are obtained in PEDOT:PSS/paper composite films, owing to the simultaneously enhanced Seebeck coefficient (30.6 μV K^?1) and electrical conductivity, and a low thermal conductivity (0.16 W m^?1 K^?1) compared with pristine PEDOT:PSS films. The results indicate that paper as an effective substrate is suitable for the preparation of high‐performance and flexible thermoelectric materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 737–742     

Small molecule-dependent genetic selection in stochastic nanodroplets as a means of detecting protein-ligand interactions on a large scale

Background: Understanding the cellular role of a protein often requires a means of altering its function, most commonly by mutating the gene encoding the protein. Alternatively, protein function can be altered directly using a small molecule that binds to the protein, but no general method exists for the systematic discovery of small molecule ligands. Split-pool synthesis provides a means of synthesizing vast numbers of small molecules. Synthetic chemists will soon be able to synthesize natural product-like substances by this method, so compatible screening methods that detect the activity of minute quantities of molecules among many inactive ones will be in demand.Results: We describe two advances towards achieving the above goals. First, a technique is described that uses a simple spray gun to create 5000–8000 droplets randomly, each having a volume of 50–200 nanoliters. The individual ‘nanodroplets’ contain a controlled number of cells and many also contain individual synthesis beads. As small molecules can be photochemically released from the beads in a time-dependent manner, the concentration of ligands that the cells are exposed to can be controlled. The spatial segregation of nanodroplets prevents the mixing of compounds from other beads so the effects of each molecule can be assayed individually. Second, a small molecule-dependent genetic selection involving engineered budding yeast cells was used to detect intracellular protein-ligand interactions in nanodroplets.Conclusions: The technique described here should facilitate the discovery of new cell-permeable ligands, especially when combined with a positive selection assay that detects intracellular binding of small molecules to proteins. Using ‘anchored combinatorial libraries’, it may be possible to screen entire libraries of natural product-like molecules against the entire collection of proteins encoded within cDNA libraries in a single experiment.     

Some aspects of the evaluation of measurement uncertainty using reference materials

 In practice there are three aspects that need to be considered in order to achieve the required traceability according to its definition: the 'stated reference', the 'unbroken chain of calibrations' and the "stated uncertainty". For a certain chemical result, each of these aspects highly depends on the measurement uncertainty, both on its magnitude and how it was estimated. Therefore, the paper describes the experience of the Romanian National Institute of Metrology in estimating measurement uncertainty during the certification of reference materials (RMs), in metrological activities (calibration, pattern approval, periodical verification, etc.), as well as during the analytical measurement process. Practical examples of estimation of measurement uncertainty using RMs or certified reference materials are discussed for their applicability in spectrophotometric and turbidimetric analysis. Use of the analysis of variance to obtain some additional information on the components of measurement uncertainty and to identify the magnitude of individual random effects is described. Received: 12 November 1999 / Accepted: 25 February 2000     

Some aspects of the evaluation of measurement uncertainty using reference materials

To ensure and to confirm the required traceability according to the definition given in the International Vocabulary of Basic and Standard Terms in Metrology, three main aspects need to be considered in practice: "stated reference", "unbroken chain of calibration" and "stated uncertainty". For a certain spectrochemical result, each of the aspects above mentioned is highly dependent on measurement uncertainty, both on its magnitude and how it was estimated. The paper describes the experience of the Romanian National Institute of Metrology (INM) in estimating measurement uncertainty during certification of reference materials, in metrological calibration and during specific analytical processes. Practical examples of the use of reference materials or certified reference materials issued by the INM to estimate measurement uncertainty are discussed for their applicability in spectrochemical and turbidity analysis. Some aspects of the use of analysis of variance (ANOVA) to obtain additional information on the components of measurement uncertainty and to identify the magnitude of individual random effects are presented.     

Some aspects of the evaluation of measurement uncertainty using reference materials

To ensure and to confirm the required traceability according to the definition given in the International Vocabulary of Basic and Standard Terms in Metrology, three main aspects need to be considered in practice: “stated reference”, “unbroken chain of calibration” and “stated uncertainty”. For a certain spectrochemical result, each of the aspects above mentioned is highly dependent on measurement uncertainty, both on its magnitude and how it was estimated. The paper describes the experience of the Romanian National Institute of Metrology (INM) in estimating measurement uncertainty during certification of reference materials, in metrological calibration and during specific analytical processes. Practical examples of the use of reference materials or certified reference materials issued by the INM to estimate measurement uncertainty are discussed for their applicability in spectrochemical and turbidity analysis. Some aspects of the use of analysis of variance (ANOVA) to obtain additional information on the components of measurement uncertainty and to identify the magnitude of individual random effects are presented.     

High‐throughput characterization of pattern formation in symmetric diblock copolymer films

Surface‐pattern formation in thin block copolymer films was investigated by utilizing a high‐throughput methodology to validate the combinatorial measurement approach and to demonstrate the value of the combinatorial method for scientific investigation. We constructed measurement libraries from images of subregions of block copolymer films having gradients in film thickness and a range of molecular mass, M. A single gradient film covers a wide range of film morphologies and contains information equivalent to a large number of measurements of films having a fixed thickness, h. Notably, the scale of the surface patterns is generally much larger than the molecular dimensions so that the interpretation of the patterns is more subtle than ordering in bulk block copolymer materials, and there is no predictive theory of this type of surface‐pattern formation. We observed a succession of surface patterns that repeat across the film with increasing h [extended smooth regions, regions containing circular islands, labyrinthine (“spinodal”) patterns, holes, and smooth regions again]. The extended smooth regions and the labyrinthine patterns appear to be novel features revealed by our combinatorial study, and these patterns occurred as bands of h that were quantized by integral multiples of the bulk lamellar period, L_o. The magnitude of the height gradient influenced the width of the bands, and the smooth regions occupied an increasing fraction of the film‐surface area with an increasing film gradient. The average size of the spinodal patterns, λ, was found to scale as λ ～ L or λ ～ M^?1.65 and reached a limiting size at long annealing times. The hole and island features had a size comparable to λ, and their size likewise decreased with increasing M. The smooth regions were attributed to an increase in the surface‐chain density in the outer brushlike block copolymer layer with increasing h, and the scaling of λ with M was interpreted in terms of the increasing surface elasticity with M. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2141–2158, 2001     

Combinatorial approach for fast screening of functional materials

We present an integrated system with automated sample fabrication for combinatorial investigations of solution-processed organic materials. To illustrate the applicability of the system, we give examples of typical experimental results with organic electronic devices. Organic light emitting diodes (OLEDs) based on a poly-(N-vinylcarbazole) matrix system with small molecule hole-transporter N,N′-Bis(3-methylphenyl)-N,N′-diphenyl-benzidine (TPD) and electron transporter 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) were optimized. In a single experimental run, the optimum range of TPD and PBD concentrations has been determined. Furthermore, we screened the influence of a gate dielectric modification with poly(methyl silsesquioxane) in organic field effect transistors and show that the choice of the material system, which constitutes the interface between the gate dielectric and the organic semiconductor, modulates the mobility of the field-effect device by more than two orders of magnitude. Finally, we present a combinatorial study of the influence of PEDOT-PSS and P3HT-PC₆₁BM layer thickness variation in organic photo voltaic cells. To summarize, we describe the possibilities of a combinatorial tool for solution based multilayer devices comprising functional materials. The tool is applicable to a vast variety of such materials. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1587–1593, 2010     

紫外吸收光谱法在高通量筛选中的应用

 与传统化合物的单独合成及结构性能测定相比,高通量筛选技术具有简化并缩短发现目标化合物过程的特点. 以紫外吸收光谱法为手段,利用高通量筛选技术考察了Co-Ce/HZSM-5对甲烷还原NOx反应的催化活性. 研制了专用的平行反应器,使每个反应通道的反应温度相同,气体空速相近; 建立了一种高通量初级筛选催化剂库的快速方法,初步评价了不同Co/Ce比的Co-Ce/HZSM-5催化剂样品的催化活性. 结果表明,当w(Co)=2.5%及m(Co)/m(Ce)=2时,催化剂的活性最高,其活性因数达到了0.67.