多功能水溶性聚合物配体制备纳米颗粒

以多功能水溶性聚合物配体制备的纳米颗粒具有小尺寸、单分散、生物相容性良好的特点,同时还具备近红外荧光、超顺磁性等特殊物理性质,弥补了传统方法制备纳米颗粒的缺陷。本文综述了近年来多功能水溶性聚合物配体制备贵金属纳米颗粒、磁性纳米颗粒、纳米量子点以及复合结构纳米颗粒的进展;阐述了多功能水溶性聚合物配体在制备纳米颗粒方面的优势;分析了多功能水溶性聚合物的结构、分子量、浓度等因素对制备纳米颗粒的影响。最后,探讨了小尺寸、单分散、水溶性的纳米颗粒在配体交换、药物靶向传输体系、疾病检测、生物标签、核磁共振成像以及光电学等领域的应用,并展望了多功能水溶性聚合物配体制备纳米颗粒的研究方向。     

水溶性疏水缔合聚合物在高岭土/水界面的吸附

表面活性剂;水溶性疏水缔合聚合物在高岭土/水界面的吸附     

聚乙烯醇调控水溶性共轭聚噻吩的光学性质

针对发光共轭聚合物稀溶液在干燥形成固体时的荧光淬灭问题, 通过高分子聚乙烯醇(PVA)的氢键网络调控水溶性共轭聚噻吩在溶液中的聚集行为和构象, 并采用不同的干燥方式实现了调控其固体光学性质的目的. 紫外-可见光吸收、荧光发射光谱测试表明, 在水溶液中PVA可以分散共轭聚合物链, 并增强其共平面性; 高温干燥后, 聚噻吩薄膜与无PVA添加的聚噻吩溶液的荧光性质相似; 而采用冷冻干燥法, 薄膜则保留了添加PVA后混合溶液的发光特性. 该结果表明, PVA对聚噻吩在溶液状态下的聚集/分子构象的调控行为随干燥方式的不同得到了不同程度的保留——高温加热干燥仅维持了PVA对聚噻吩的分散作用; 而冷冻干燥则完整保留了PVA与聚噻吩的分子间相互作用, 将溶液中分子的分散状态和构象同时固定. 本研究从干燥方式的角度为固态共轭聚合物聚集行为及发光性质的调控提供了新的策略.     

蛋白质与高分子的自组装

蛋白质是一类具有独特三维空间结构的生物高分子,其分子内部非共价键协同作用是形成三维空间结构的重要驱动力。同时,蛋白质分子与其他高分子之间也可以通过非共价键作用实现自组装。高分子链和蛋白质的结构特征是实现自组装的关键,溶液pH值、离子强度以及温度的变化会影响它们之间非共价键作用的类型和强度。本文归纳了水溶性高分子、嵌段共聚物和多糖与球状蛋白自组装的最新研究进展,分别从分子结构特征和溶液性质等因素讨论了其对高分子与蛋白质实现自组装的影响。其中,多糖与蛋白质的非共价键作用是化学与生物科学交叉领域最为活跃的研究课题之一,通过研究蛋白质与其他高分子的非共价键作用,对于理解和认识生命过程的本质与规律具有重要的意义,同时,在材料科学、纳米技术、食品科学等相关领域具有重要的应用价值。     

多组分聚合物体系的动态流变行为与其相行为的关系

对多组分聚合物体系相行为所采用的常规研究方法都存在不可避免的缺陷。而用动态流变学方法研究具有独特的优点,其理论依据是：对具有临界相行为(LCST、UCST)或微相分离行为的多组分聚合物体系,在小应变状态下的动态流变行为对体系在相分离过程中形态和结构的形成与演化极其敏感,非均相结构的产生使体系在长时松弛区域表现出与均相聚合物体系不同的粘弹松弛行为,即弹性显著增加、松弛时问明显增长以及时-温叠加原理失效,偏离经典的线性粘弹理论模型。本文综述了用Han曲线、Cole-Cole曲线、时-温叠加失效和G′-T曲线等动态流变学方法对多组分聚合物体系相行为的研究进展。     

水溶性荧光共轭聚合物在检测出血热病毒中的应用

利用出血热病毒抗体-L133/抗原-EHF对水溶性荧光共轭聚合物聚(5-甲氧基-2-(3-磺酰化)丙氧基-1,4-对苯撑乙烯), (简写为MPS-PPV)荧光的增强/猝灭作用、抗原-EHF与抗体-L133之间的特异性相互作用及作用前后荧光强度的变化, 建立了一种基于水溶性荧光共轭聚合物荧光猝灭可逆的高灵敏、均相免疫测定新方法, 实现了出血热病毒抗 原-EHF的快速、灵敏检测, 检测抗原-EHF的线性范围是4.8×10^－9～5.0×10^－8 mol/L, 检出限为1.7×10^－9 mol/L. 实验表明, 生物分子对聚合物的荧光增强或猝灭不仅是静电作用, 而且还表现为聚合物形态构造的变化.     

高分子研究中的一个知识问题——柔性链“从线团到小球”的构象变化

一条大分子链由许多小分子通过共价键连接而成.正是这一"连接"导致了大分子一些独特的物理性质及相关问题.本文希望阐明的就是这样一个小分子物理中没有的知识问题:小分子在溶剂中仅有溶或不溶2个状态;而自60年代起,理论学家们就预言一条柔性大分子链在溶解的状态下,其构象随着溶剂性质变差可以从无规线团蜷缩成一个单链小球.为了证明这一构象变化,实验学家们从70年代末起进行了大量的研究,直至90年代初期仍未观察到稳定的单链蜷缩小球.实验上这一长期悬而未解的问题困惑着众多研究者.甚至有理论学家在1993年报道,当今的样品制备和实验手段无法观察到一个热力学稳定的单链蜷缩小球.中国钱人元先生和一些其他研究者自80年代末期也开始关注与单链有关的问题.我们实验室从1993年开始另辟蹊径,通过制备和采用窄分布的热敏性水溶性高分子超长链,终于在1995年利用激光光散射首次观察到理论上预测的"线团到小球"的构象变化.随后,又揭示了变化过程中存在着一个全新的"融化球"构象以及在单链蜷缩小球中并无理论上预计的额外链互穿和打结.从得到的稳定单链蜷缩小球出发,我们又首次在实验上研究了"小球到线团"的过程,意外地观察到其在准理想状态附近滞后于"线团到小球"的构象变化,并证明该滞后可归于链蜷缩过程中形成的额外链内氢键.最后,借用红外纳秒脉冲激光加热的方法研究了"线团到小球"的蜷缩动力学,并发现其包含了在单个高分子链上"成核"和"粗化"先后2个过程.其中,"成核"过程与链长无关.经过近20年的努力,我们终于基本解决了这一近代高分子物理研究中与知识有关的重要问题,揭示了与其相关的一些大分子特有的物理性质.     

水溶性二铁六羰基配合物与生物相关分子的相互作用及其促进一氧化碳释放

二铁六羰基配合物[Fe₂（μ-SCH₂R）₂（CO）6]（R=CH （OH） CH₂（OH）,1）是一个水溶性且能够释放一氧化碳的分子（CORM）,我们应用各种光谱技术研究了其与血红蛋白（Hb）、肌红蛋白（Mb）、牛血清白蛋白（BSA）、谷胱甘肽（GSH）和DNA等生物分子的相互作用。红外光谱结果表明,蛋白质和谷胱甘肽均能促进配合物1分解释放CO。该CO释放过程符合一级动力学模型,其中谷胱甘肽促进CO释放的效率最高。紫外吸收光谱变化和荧光猝灭效应也表明这些生物相关分子与二铁羰基配合物之间存在相互作用。蛋白质和配合物1的CD光谱结果显示,配合物没有引起蛋白质的构象变化。pUC19质粒DNA与配合物1之间的作用表明该配合物不会引起DNA损伤。     

Modification of Recycled Polymer Blends with Activated Natural Zeolite

The growing interest in the natural zeolite is based on some specific peculiarities of its structure, which after dehydration enables adsorption processes of some polymer molecules and/or segments to take place on the zeolite surface. The main goal of the study is to investigate the effect of dehydrated zeolite on the flow behavior, mechanical properties and morphology of immiscible blends from unsorted polymer wastes. A tetra-component blend consisting of 40 wt.% polypropylene (PP), 40 wt.% high-density polyethylene (HDPE), 15 wt.% low-density polyethylene (LDPE) and 5 wt.% polystyrene (PS), was studied as a model system of commingled plastic wastes. Compositions from recycled blend and dehydrated zeolite in a wide concentration range (from 0 to 20 wt.%) were prepared using a twin-screw extruder Brabender DSE 35/17D in the temperature range from 140 to 190 °C. The compositions were characterized by capillary rheometry, differential scanning calorimetry (DSC), site-resolved wide-angle X-ray scattering (WAXS) and mechanical tests. The results show a compatibilizing effect of dehydrated zeolite at low concentration levels (1-2 wt.%) and open wide possibilities for utilization of dehydrated zeolite in the recycling of unsorted polymer wastes.     

A Water-Soluble Sodium Pectate Complex with Copper as an Electrochemical Catalyst for Carbon Dioxide Reduction

A selective noble-metal-free molecular catalyst has emerged as a fruitful approach in the quest for designing efficient and stable catalytic materials for CO₂ reduction. In this work, we report that a sodium pectate complex of copper (PG-NaCu) proved to be highly active in the electrocatalytic conversion of CO₂ to CH₄ in water. Stability and selectivity of conversion of CO₂ to CH₄ as a product at a glassy carbon electrode were discovered. The copper complex PG-NaCu was synthesized and characterized by physicochemical methods. The electrochemical CO₂ reduction reaction (CO₂RR) proceeds at −1.5 V vs. Ag/AgCl at ~10 mA/cm² current densities in the presence of the catalyst. The current density decreases by less than 20% within 12 h of electrolysis (the main decrease occurs in the first 3 h of electrolysis in the presence of CO₂). This copper pectate complex (PG-NaCu) combines the advantages of heterogeneous and homogeneous catalysts, the stability of heterogeneous solid materials and the performance (high activity and selectivity) of molecular catalysts.     

聚合物分散剂对氟铃脲水悬浮剂流变性质的影响

采用控制应力流变仪研究了聚合物分散剂苯乙烯丙烯酸无规共聚物（MOTAS）用量、分子量及氟铃脲质量分数等对氟铃脲水悬浮剂流变性质的影响。 结果表明,以聚合物MOTAS为分散剂制备的氟铃脲水悬浮剂的流变行为符合Herschel-Bulkley模型。 在固定氟铃脲质量分数为20%时,当分散剂质量分数≤3.0%时,流动行为指数n≤1.0,悬浮体系表现为假塑性流体,当分散剂质量分数≥3.5%时,流动行为指数n≥1.0,悬浮体系具有胀塑性流体特征。 氟铃脲水悬浮剂的流变参数屈服值τH与分散剂MOTAS和氟铃脲的加入量有关。 分散剂MOTAS质量分数≤2.5%时,分散剂在氟铃脲颗粒界面吸附很少,裸露的氟铃脲颗粒界面间相互搭接,具有较大的屈服值τH;当分散剂加入质量分数为3.0%时,分散剂可在氟铃脲颗粒界面形成饱和吸附,若再增加分散剂用量,多余分散剂在悬浮的氟铃脲颗粒间形成搭接,使其屈服值τH增大。 在MOTAS分散剂的分子量在10 000~30 000范围内时,MOTAS分子量愈大,所制得的氟铃脲水悬浮剂的表观粘度和屈服值τH愈小,流变行为指数n虽略有增加,但均小于1,没有改变“剪切变稀”的假塑性特征。     

Polymer decoration study in chain folding behavior of solution-grown poly(ethylene oxide) crystals

The polymer decoration method based on the vaporization and condensation-crystallization of polyethylene (PE) upon the fold surface of polymer crystals has been widely used to study the chain folding behavior of the crystals. When this method was utilized to study solution-grown high molecular weight poly (ethylene oxide) (PEO) lamellar crystals, the highly anisotropic, low molecular weight fragment PE decorated become oriented parallel to the fold direction and form rods, which can be observed by transmission electron microscopy (TEM) and electron diffraction (ED). The growth sectors were clearly observed. From the ED patterns the {200} planes of the orthorhombic low molecular weight PE rod crystals can be observed, and the c-axis of these crystals is aligned parallel to the {120} growth planes of the PEO crystals. The decoration results indicate that the major fold orientation of high molecular weight PEO single crystals grown from dilute solution is along the {120} planes. © 1995 John Wiley & Sons, Inc.     

Structural-Deformation-Energy-Modulation Strategy in a Soft Porous Coordination Polymer with an Interpenetrated Framework

To achieve unique molecular-recognition patterns, a rational control of the flexibility of porous coordination polymers (PCPs) is highly sought, but it remains elusive. From a thermodynamic perspective, the competitive relationship between the structural deformation energy (E_def) of soft PCPs and the guest interaction is key for selective a guest-triggered structural-transformation behavior. Therefore, it is vital to investigate and control E_def to regulate this competition for flexibility control. Driven by these theoretical insights, we demonstrate an E_def-modulation strategy via encoding inter-framework hydrogen bonds into a soft PCP with an interpenetrated structure. As a proof of this concept, the enhanced E_def of PCP enables a selective gate-opening behavior toward CHCl₃ over CH₂Cl₂ by changing the adsorption-energy landscape of the compounds. This study provides a new direction for the design of functional soft porous materials.     

Water-Soluble Polyacids with Capability to Remove Metal Ions in Homogenous Phase by Using the Liquid Phase Polymer-Based Retention Technique

Water-soluble polymers containing carboxylic acid and sulfonic acid groups were investigated as polychelatogens under different experimental conditions in view to study their metal ion binding properties, using the liquid-phase polymer-based retention technique. The divalent metal ions investigated were: Co²⁺, Cu²⁺, Zn²⁺, and Cd²⁺. When the pH increased above 3, and especially at pH 5, metal ion retention capability increased as the majority of the functional groups are carboxylate, which can form more stable complexes with the metal ions. The retention capability also depended on the structure of the polyacid and the filtration factor, Z.     

Application of FTIR Microscopy in Combinatorial Experimentation on Polymer Blends

Summary: A novel combinatorial, high-throughput experimentation (HTE) setup has been developed, which allows for rapid mapping of the phase behavior of blends of homopolymers and block copolymers. The principle is based on the preparation of composition (ϕ)-temperature (T) gradient films. Linear ϕ gradients were obtained over a large composition range, as shown by FTIR microscopy. The applicability of this combinatorial approach was demonstrated by studying the phase behavior of a poly(styrene-co-acrylonitrile) (SAN)/poly(methyl methacrylate-co-ethyl acrylate) (PMMA-EA) blend with varying EA content and a poly(styrene-b-butadiene-b-methyl methacrylate) (SBM) triblock copolymer.     

Rheological behavior and prediction for blending conditions of a thermotropic liquid crystalline polyester with nylon

The dynamic rheological behavior of a liquid crystalline polymer (LCP), Vectra™ A, and nylons was investigated. The viscosities of nylon 66 and nylon 6 decrease slowly with an increase in temperature, while the viscosity of Vectra A drops dramatically at 280 °C, but remains slightly changed above 300 °C. At constant frequency and above 300 °C, the mean value of the activation energy of Vectra A is about 87.0 kJ/mole, but jumps to a much higher value of about 407.0 kJ/mole if the melt temperature is below 300 °C. The activation energy of Vectra A above 300 °C is lower than nylon 66, which shows that the viscosity of nylon 66 has a greater temperature dependence than Vectra A. The viscosity ratio of Vectra A to Nylon 66 is less than 1 at temperatures higher than 290 °C, which indicates that Vectra A can form the fibrils in the nylon 66 matrix and reinforce nylon 66 when blending them above this temperature. Experimental data confirm our prediction. Copyright © 2000 John Wiley & Sons, Ltd.     

酞菁钴－高分子双层膜修饰电极对氧的催化电还原

酞菁钴－高分子双层膜修饰电极对氧的催化电还原董国孝，李纪生，庄瑞舫（中国科学院北京化学研究所，北京，１０００８０）（南京大学配位化学研究所）关键词酞菁合钴，双层膜修饰电极，电还原金属酞菁配合物的催化活性和电催化活性已引起化学家们的极大兴趣，它们作为电...     

剪切流动对聚合物共混物相行为影响的研究进展

剪切流动对聚合物共混物相行为影响的研究进展;综述