分子印迹聚合物微球制备方法研究进展

分子印迹聚合物微球具有制备简单、使用方便、分子识别效率高且便于控制粒径大小和功能设计等优点，近年来成为分子印迹技术领域研究的热点之一。对分子印迹聚合物微球的制备方法：溶胀悬浮聚合法、沉淀聚合法、悬浮聚合法和表面聚合法及其最新研究进展作了较为详细的综述。     

活性自由基聚合的白藜芦醇分子印迹聚合物的合成及在葡萄皮白藜芦醇分析中的应用

RAFT试剂介入制备白藜芦醇分子印迹聚合物并用于实际样品中白藜芦醇的分离富集。以二苄基三硫代碳酸酯(DBTTC)为RAFT试剂,以白藜芦醇为印迹化合物,以丙烯酰胺作为功能单体,利用可逆加成-断裂链转移自由基聚合法(RAFT)制备了白藜芦醇分子印迹聚合物。利用扫描电镜、红外光谱和色谱法考察了单体与交联剂比例、引发剂用量、溶剂用量、反应时间和反应温度对印迹聚合物形态结构、印迹聚合物的识别能力及分离效率的影响。结果显示,利用RAFT聚合法制备的白藜芦醇分子印迹聚合物对模板分子的结合量Q达到1 283μg/g,并具有特异性识别作用。通过活性自由基聚合法合成的分子印迹聚合物具有更好的形态结构,对目标分子具有较高的吸附效率。     

分子印迹聚合物微球合成方法研究进展

对近年来发展起来的分子印迹聚合物微球(MIPMs)合成方法的研究进展进行了综述。重点介绍了表面分子印迹聚合物合成法、核-壳型分子印迹聚合物合成法、基于β-环糊精分子印迹聚合物的合成法3种新型MIPMs制备方法。阐述了常用的沉淀聚合法、种子溶胀聚合法、悬浮聚合法合成MIPMs的发展现状。最后对MIPMs的发展趋势提出了展望。     

盐酸二甲双胍磁性分子印迹聚合微球的合成

以盐酸二甲双胍为模板分子、Fe_3O_4为磁核、α-甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂、偶氮二异丁腈为引发剂,采用表面印迹聚合法成功制备了对盐酸二甲双胍具有特异性识别功能的磁性分子印迹聚合微球。合成的磁性聚合物具有良好的磁响应,在外加磁场下可实现快速磁分离。红外光谱、X射线光电子能谱和扫描电镜结果证实聚合物为核壳结构,磁性粒子由硅烷偶联剂完全包覆,并在其表面形成了一层分子印记聚合物。静态吸附实验结果表明,制备的磁性分子印迹聚合物对模板分子盐酸二甲双胍具有良好的吸附能力,其饱和吸附量为83mmol/kg。以双胍类降糖成分盐酸丁二胍和盐酸苯乙双胍为竞争分子,磁性印迹聚合物对模板分子表现出良好的特异选择性。     

以硅材料为载体的表面分子印迹技术研究新进展

硅材料具有良好的力学稳定性和热稳定性,作为表面分子印迹聚合物的载体具有较大的优势.以硅材料为载体的表面分子印迹聚合物(SSMIP)是目前分子印迹技术领域的研究重点之一.着重对最近几年SSMIP的制备方法进行总结与评述,主要包括接枝共聚法、活性可控自由基聚合法、牺牲硅胶骨架法和溶胶-凝胶法等,并对SSMIP的应用和未来发展进行了展望.     

分子印迹聚合物的热力学与物理表征及模拟研究进展

分子印迹聚合物(MIPs)是一种对目标分子具有特异选择性和识别能力的高分子功能材料。文中从印迹聚合物预聚复合物的形成,聚合过程中印迹网络的构成以及聚合后的吸附性能及吸附位点等几方面综述了分子印迹聚合物的热力学、物理表征和模拟在分子印迹聚合物理论研究中的进展。     

分子印迹技术在药物缓释领域的研究进展

分子印迹技术是制备对特定分子结构具特异性识别功能的聚合物的一项重要技术,其在药物缓释领域的应用越来越引起研究者们的重视。在介绍了分子印迹技术的概念及原理的基础上,提出了应用于药物传输领域的分子印迹聚合物所应当具备的特性,综述了近年来分子印迹技术在药物传输领域的研究进展。并指出:为提高聚合物作为药物载体的生物顺应性,在水相中对聚合物的合成、可控自由基聚合制备规格统一的聚合物及将分子印迹聚合物应用于智能医用材料领域将成为日后研究的主流。     

悬浮聚合法制备功能型甲基丙烯酸酯类聚合物的研究与应用

甲基丙烯酸酯类微球具有与生物样品相容性好、易于修饰、无毒副作用等特点,在生物生化领域中具有重要作用。悬浮聚合法步骤简单、产物处理方便,是最常用的聚合物制备方法。以微球粒径及孔结构为指标,系统综述了悬浮聚合法制备甲基丙烯酸酯类聚合物的各个影响因素,并总结了此类填料在酶的固定化、分子印迹聚合物的制备、药物载体及金属离子吸附等方面的应用,最后对甲基丙烯酸酯类微球的发展趋势进行了展望。     

分子印迹聚合物的设计与制备

对分子印迹聚合物的设计、制备及其特性以及分子印迹技术的未来发展方向进行简要评述。过程及方法：概述了分子印迹技术的原理和特点，重点介绍了分子印迹聚合物的制备和特性，最后分析了分子印迹技术目前存在的一些突出问题。结果及应用范围：作为一种制备具有亲和性和选择性高、稳定性好的分子印迹聚合物的技术，分子印迹以其简便、通用和高效等特点吸引了研究者的广泛兴趣。分子印迹聚合物在分离分析、仿生传感器和模拟酶催化等领域将具有重要的应用前景。     

L-苹果酸分子印迹聚合物微球的制备及性能评价

以L-苹果酸为模板分子,丙烯酰胺(AA)、乙二醇二甲基丙烯酸酯(EGDMA)分别为功能单体和交联剂,采用沉淀聚合法制备了分子印迹聚合物微球,研究了聚合体系组成对模板聚合物吸附特性的影响。实验表明,以1∶4∶20的物质的量比加入模板分子、AA和EGDMA时,制备的模板聚合物吸附容量高,印迹效果好。通过Scat-chard分析研究了聚合物的选择结合性能,结果表明分子印迹聚合物微球在识别L-苹果酸的过程中存在2类结合位点,而空白印迹聚合物微球只存在1类结合位点。印迹聚合物微球对L-苹果酸和D-苹果酸的手性分离因子α达2.05。     

Carbon nanocones: wall structure and morphology

Abstract

Large-scale production of conical carbon nanostructures is possible through pyrolysis of hydrocarbons in a plasma torch process. The resulting carbon cones occur in five distinctly different forms, and disc-shaped particles are produced as well. The structure and properties of these carbon cones and discs have been relatively little explored until now. Here we characterize the structure of these particles using transmission electron microscopy, synchrotron x-ray and electron diffraction. The carbon nanocones are found to exhibit several interesting structural features; instead of having a uniform cross-section, the walls consist of a relatively thin inner graphite-like layer with a non-crystalline envelope, where the amount of the latter can be modified significantly by annealing. The cones appear with a well-defined faceting along the cone edge, demonstrating strict long-range atomic ordering; they also present occasional examples of symmetry breaking, such as two apexes appearing in the same carbon nanocone.     

环境扫描电子显微镜的特性及应用概况

简要叙述了环境扫描电子显微镜的原理，着重介绍了它的特性和在国内外应用的概况。与普通的扫描电子显微镜相比，它具有能直接检测不导电样品和含油含水样品的独特性能，为扫描电子显微镜的应用开拓了新的领域。     

Carbon nanocones: wall structure and morphology

Large-scale production of conical carbon nanostructures is possible through pyrolysis of hydrocarbons in a plasma torch process. The resulting carbon cones occur in five distinctly different forms, and disc-shaped particles are produced as well. The structure and properties of these carbon cones and discs have been relatively little explored until now. Here we characterize the structure of these particles using transmission electron microscopy, synchrotron x-ray and electron diffraction. The carbon nanocones are found to exhibit several interesting structural features; instead of having a uniform cross-section, the walls consist of a relatively thin inner graphite-like layer with a non-crystalline envelope, where the amount of the latter can be modified significantly by annealing. The cones appear with a well-defined faceting along the cone edge, demonstrating strict long-range atomic ordering; they also present occasional examples of symmetry breaking, such as two apexes appearing in the same carbon nanocone.     

Optical Calibration of a Submicrometer Magnification Standard

The calibration of a new submicrometer magnification standard for electron microscopes is described. The new standard is based on the width of a thin thermal-oxide film sandwiched between a silicon single-crystal substrate and a polysilicon capping layer. The calibration is based on an ellipsometric measurement of the oxide thickness before the polysilicon layer is deposited on the oxide. The uncertainty in the derivation of a thickness for the layer from the ellipsometric parameters is also derived.     

扫描电镜中荷电效应的分析

扫描电子显微镜要得到层次清晰、立体感强且分辨率高的高质量图像,荷电效应是一个重要的影响因素。对在扫描电子显微镜成像中荷电效应的成因及其解决办法进行了系统的分析。提出采用镀膜、降低加速电压及低真空的方法,可降低荷电效应的影响。     

Phase Identification in a Scanning Electron Microscope Using Backscattered Electron Kikuchi Patterns

Backscattered electron Kikuchi patterns (BEKP) suitable for crystallographic phase analysis can be collected in the scanning electron microscope (SEM) with a newly developed charge coupled device (CCD) based detector. Crystallographic phase identification using BEKP in the SEM is unique in that it permits high magnification images and BEKPs to be collected from a bulk specimen. The combination of scanning electron microscope (SEM) imaging, BEKP, and energy dispersive x-ray spectrometry holds the promise of a powerful new tool for materials science.     

Spin Fluctuation Effect on Electron-Electron Coupling in High Temperature Superconductors

The spin fluctuation effect on the electron-phonon coupling factor has been calculated. The system is considered to be two-dimensional and we consider two different models which describe the spin fluctuations. These models correspond to strongly correlated electron systems. The effect of disorder introduced by nonmagnetic impurities is investigated.     

Hollow Ptychography: Toward Simultaneous 4D Scanning Transmission Electron Microscopy and Electron Energy Loss Spectroscopy

With the recent development of high-acquisition-speed pixelated detectors, 4D scanning transmission electron microscopy (4D-STEM) is becoming routinely available in high-resolution electron microscopy. 4D-STEM acts as a “universal” method that provides local information on materials that is challenging to extract from bulk techniques. It extends conventional STEM imaging to include super-resolution techniques and to provide quantitative phase-based information, such as differential phase contrast, ptychography, or Bloch wave phase retrieval. However, an important missing factor is the chemical and bonding information provided by electron energy loss spectroscopy (EELS). 4D-STEM and EELS cannot currently be acquired simultaneously due to the overlapping geometry of the detectors. Here, the feasibility of modifying the detector geometry to overcome this challenge for bulk specimens is demonstrated, and the use of a partial or defective detector for ptycholgaphic structural imaging is explored. Results show that structural information beyond the diffraction-limit and chemical information from the material can be extracted together, resulting in simultaneous multi-modal measurements, adding the additional dimensions of spectral information to 4D datasets.     

有关电子显微技术的几个实验和建议

本文涉及两个和电子显微技术有关的问题：豆．透射电子显微镜试样薄片表面沉淀相颗粒存在状况的实验观察．２．扫描电子显微镜背反射电子象用作定量金相测定的建议。