基于聚乙烯醇聚合物点制备荧光纳米复合材料

近年来, 由于聚合物点(PDs)具有良好的荧光性质和光收集能力, 受到了人们广泛的关注, 应用在生物成像和检测等领域. 然而, 目前报道的聚合物点大多数是指共轭聚合物经过组装、固定形成的, 因此聚合物点保持着形成之前的共轭聚合物的相关性质, 且具有更好的稳定性和进一步功能化的能力. 本文中我们研究的聚合物点是指从非共轭线性聚合物为原料而制备的聚合物点, 这类聚合物包括聚环氧乙烯, 多糖等. 聚合物点不仅包含使其具有荧光的碳化中心, 还具有外围的聚合物链结构. 因此, 可以拓展应用聚合物点的聚合物特性. 我们利用PDs的荧光中心和外围的聚合物链双功能性质, 详细研究了基于PDs制备功能性纳米复合材料体系. 首先, 我们原位制备了聚乙烯醇/PDs纳米复合膜材料(PDs是直接通过聚乙烯醇可控碳化而产生的). 复合材料不仅保持了PDs的荧光特性, 还保持了聚乙烯醇易加工的特性, 如可以制备成纳米复合膜材料, PDs含量可以根据需要调控: 0, 20%, 40%, 60%, 80%, 100%. 纳米复合膜材料在不同激发光下具有多颜色发光性质. 进一步的, 我们验证了PDs水溶液可以和很多其他水溶性聚合物, 石墨烯量子点或半导体量子点实现共混, 从而制备双功能性纳米复合材料.     

花菁染料负载的聚合物纳米材料用于次氯酸可视化检测的研究

次氯酸(HClO)作为强氧化剂被广泛应用于日常生活中,研究对HClO浓度的便捷监测方法具有重要意义。针对HClO的可视化探针存在水溶性较差和易被光漂白的问题,本工作利用次氯酸根(ClO-)可破坏花菁染料的共轭结构这一特性,设计合成了一种花菁染料Cy7负载的聚苯乙烯纳米球(PS-Cy7),并研究了其与次氯酸的响应行为。实验结果表明,PS-Cy7具有良好的单分散性,粒径约为78nm;相比于花菁染料Cy7,PS-Cy7具有更好的水溶性和光稳定性,并且对次氯酸具有专一性的响应,其最低检测限为0.22μmol/L,实现了对HClO的可视化检测,有望用于日常生活中的HClO监测。     

The Mechanical Deformation Process of Electrospun Polymer Nanocomposite Fibers

Summary: The mechanical deformation processes of poly(methyl methacrylate)/ montmorillonite nanocomposites and their electrospun fibers were investigated by in situ tensile tests under a transmission electron microscope depending on their morphology. While the polymer nanocomposites deformed in a brittle manner, i.e., crazing, the electrospun polymer nanocomposite fibers deformed through a shear flow process leading to “nanonecking” due to the strong overlap of stress fields caused by nanopores within the fiber under a uniaxial tensile load. This unique change in deformation behavior provides the possibility that the intrinsic brittle material could be manipulated to be ductile without sacrificing its other attractive properties through a well‐controlled electrospinning process.

TEM micrograph of a low temperature fractured fiber showing the nanoporous surface structure.     

Dissipative Particle Dynamics Simulations of Polymer Brushes: Comparison with Molecular Dynamics Simulations

Summary: The structure of polymer brushes is investigated by dissipative particle dynamics (DPD) simulations that include explicit solvent particles. With an appropriate choice of the DPD interaction parameters , we obtain good agreement with previous molecular dynamics (MD) results where the good solvent behavior has been modeled by an effective Lennard–Jones potential. The present results confirm that DPD simulation techniques can be applied for large length scale simulations of polymer brushes. A relation between the different length scales and is established.

Polymer brush at a solid–liquid interface.     

Photochromism of Peroxotungstic Acid/PVP Nanocomposite Obtained by Sol-Gel Method

Peroxotungstic acid (PTA)/PVP composite film was prepared via sol-gel method. TEM revealed that the composite films consist of peroxotungstic acid nano-grains embedded in amorphous PVP matrix. The samples were observed to exhibit reversible photochromic effect when irradiated with solar light. The iodometric titration and FT-IR spectra indicated the presence of peroxo groups (W–O–O–W) incorporated into PTA structure. EPR measurement revealed the presence of unpaired paramagnetic electrons in PTA/PVP nanocomposite gel. The UV-Vis-Nir transmittance spectra and EPR spectroscopy of sample indicate that the photochromic behaviour is due to the photo-excitation of the unpaired electrons at W–O octahedral sites of peroxotungstic acid.     

Electrochemical Pseudocapacitors Based on Ternary Nanocomposite of Conductive Polymer/Graphene/Metal Oxide: An Introduction and Review to it in Recent Studies

This review gives an overview of the synthesis, surface and electrochemical investigations over ternary nanocomposite of conductive polymers in the development of new supercapacitors. They utilize both Faradaic and non‐Faradaic procedures to store charge, leading to higher specific capacitance and energy density, higher cell voltage, longer life cycle and moderated power density. Owing to a unique combination of features such as superb electrical conductivity, corrosion resistance in aqueous electrolytes, highly modifiable nanostructures, long cycle life and the large theoretical specific‐surface area, the use of ternary nanocomposites as a supercapacitor electrode material has become the focus of a significant amount of current scientific researches in the field of energy storage devices. In these nanocomposites, graphene not only can be utilized to provide a substrate for growing nanostructured polymers in a polymer‐carbon nanocomposite structure in order to overcome the insulating nature of conductive polymers at dedoped states, but also is capable of providing a platform for the decoration of metal oxide nanoparticles to avoid their agglomeration. In this regard, synthesis, characterization and performance of different ternary nanocomposites of conductive polymer/graphene/metal oxide are discussed in detail. These remarkable results demonstrate the exciting commercial potential for high performance, environmentally friendly and low‐cost electrical energy storage devices based on ternary nanocomposite of conductive polymer/graphene/metal oxide.     

分子印迹聚合物修饰电化学晶体管检测抗坏血酸分子

以抗坏血酸(AA)为模板分子、邻苯二胺(o-PD)为功能单体,在金电极表面电聚合制备分子印迹聚合物膜(MIP),并以该MIP修饰的电极为栅极制备了具有高选择性、高灵敏度的AA电化学晶体管(OECT)传感器件。应用循环伏安法(CV)、交流阻抗法(EIS)对分子印迹聚合物电极进行一系列的表征与检测。实验结果表明:以pH=5.2,浓度为0.2mol/L HAc-NaAc(体积比2.1∶7.9)的缓冲液为背景溶液,o-PD与AA的物质的量之比为1∶2,以0.5V/s的扫描速率在0~0.8V内扫描20圈,所得分子印迹膜电极性能最佳。应用以该分子印迹修饰电极作为栅极的电化学晶体管检测AA,得到AA浓度的检测限为0.3μmol/L,沟道电流与AA浓度在0.3~3μmol/L(低浓度)与3~100μmol/L(高浓度)这2个范围内成线性关系。     

Reduction of the effective shear viscosity in polymer solutions due to crossflow migration in microchannels: Effective viscosity models based on DPD simulations

Molecular dynamics simulations (dissipative particle dynamics–DPD) were developed and used to quantify wall-normal migration of polymer chains in microchannel Poseuille flow. Crossflow migration due to viscous interaction with the walls results in lowered polymer concentration near the channel walls. A larger fraction of the total flow volume becomes depleted of polymer when the channel width h decreases into the submicron range, significantly reducing the effective viscosity. The effective viscosity was quantified in terms of channel width and Weissenberg number Wi, for 5% polymer volume fraction in water. Algebraic models for the depletion width δ(Wi, h) and effective viscosity μ_e(δ/h, Wi) were developed, based on the hydrodynamic theory of Ma and Graham and our simulation results. The depletion width model can be applied to longer polymer chains after a retuning of the polymer persistence length and the corresponding potential/thermal energy ratio.     

基于共轭高分子纳米复合材料发光二极管的研究进展

简要介绍了发光二极管 (LED)的发展历程和发光机理 ,着重论述了共轭聚合物纳米复合材料在LED发光层上的应用 ,讨论了基于提高发光器件光电性能和环境稳定性的纳米复合材料结构的设计及目前需要解决的问题。     

基于聚乳酸的可降解形状记忆高分子的研究进展

综述了基于聚乳酸的可生物降解的形状记忆高分子材料的研究情况。首先介绍了形状记忆高分子材料的记忆效应、记忆机理,然后讨论了基于聚乳酸的三种类型的形状记忆高分子材料：单组份的聚乳酸类、聚乳酸共聚物类以及聚乳酸与无机物的复合材料,分别介绍了各种类型的形状记忆高分子材料的形状记忆性能和生物降解性能。最后,讨论了聚乳酸类记忆材料的应用情况,并对其研究前景和发展趋势进行了展望。     

Effect of Chain Stiffness on Nanoparticle Segregation in Polymer/Nanoparticle Blends Near a Substrate

Nanoparticles in a flexible polymer melt film often segregate to the substrate due to attractive depletion interactions between the nanoparticles and the substrate. Here, molecular dynamics simulations are performed to study the effect of chain stiffness on this segregation. The nanoparticles are modeled as spheres and the polymers as semi‐flexible bead‐spring chains. Both purely repulsive and attractive forces are considered, while assuming non‐selective interactions among all species. The nanoparticles are found to be well‐dispersed in the system having repulsive forces only and aggregate into clusters in the completely attractive system. For the repulsive system, adding chain stiffness substantially decreases the nanoparticles' segregation, and hence their concentration, at the substrate.

     

分子印迹Mn掺杂ZnS量子点磷光法检测烟酸转化液中的6-羟基烟酸

以6-羟基烟酸(6-HNA)为模板,采用分子印迹溶胶-凝胶法合成了具有良好光学性质的印迹Mn掺杂Zn S量子点磷光传感器(MIP-QDs)。红外光谱(FT-IR)和扫描电镜(SEM)测试表明,印迹聚合物成功接枝在纳米传感器表面。吸附试验显示,MIP-QDs对6-HNA的亲和性与选择性显著高于其结构类似物阔马酸和烟酸,具备作为检测探针的潜力。在最优条件下,基于6-HNA可选择性猝灭MIP-QDs磷光而建立了灵敏、简便的检测微量6-HNA的光学新方法。当6-HNA浓度在3.4~67.0μmol/L范围内,MIP-QDs的磷光猝灭率P_0/P随浓度变化的关系符合Stern-Volmer方程(r~2=0.996 5),检出限为1.03μmol/L。实际样品测定显示,6-HNA的回收率为91.0%~103.9%,相对标准偏差不超过4.5%,检测结果与HPLC法相一致(P0.05),方法具有良好的准确性和可行性。     

Infrared Electroluminescence in Polymer Composites Based on Organic Nanocrystals

Electroluminescence in polymer nanocomposite structures with electron–hole transport, called J-aggregates, which are based on aromatic polyimides and nanosized crystals of cyanine dyes, is studied. In the near-IR range, the electroluminescence with a narrow emission spectrum (with a maximum at 815 nm) is observed for the first time. It is shown that not only are the organic nanosized crystals of the J-aggregates effective acceptors of the exciton state energy, but they play the role of active electron–hole transport centers in these novel polyfunctional polymer materials.     

磷钨酸-PVA复合体系膜的制备和光色性研究

用旋转涂布法制得了PVA -H3PW1 2 O40 复合体系的光敏膜。研究了膜对光的响应情况 ,发现复合体系对光的响应情况与体系内各成份的浓度无关。光敏性的产生源于体系内PVA的 OH与钨磷酸阴离子中Oc的相互作用。     

基于2,6-吡啶二甲酸聚合膜固定纳米金胶的过氧化氢传感器的研究

构造了一种以2,6-吡啶二甲酸电聚合膜为基底,以共价键合的半胱胺固定的纳米金胶吸附辣根过氧化物酶的过氧化氢生物传感器.在以对苯二酚作介体的条件下,实现电流的多级放大.该传感器与2,6-吡啶二甲酸聚合膜-辣根过氧化物酶修饰的传感器比较,具有更高的稳定性、更低的检测下限.在工作电位-0.1 V条件下,能快速催化还原过氧化氢.在传感器制作中,酶固定方法简单易行,制得的电极可多次重复使用,具有较好的使用价值.     

毛细管电泳中聚合物溶液筛分脱氧核糖核酸

围绕着毛细管电泳中聚合物溶液筛分脱氧核糖核酸（ＤＮＡ）的机理和分离介质、条件,综述了近年来该技术的发展,及其在ＤＮＡ测序、聚合酶链反应（ＰＣＲ）产物分析方面的应用及其发展前景。     

富勒烯稠合体与共轭聚合物作为有机太阳能电池材料的研究进展

介绍了有关富勒烯与共轭聚合物超快光诱导电子的研究状况和三种不同光敏层材料制备的太阳能电池的组装和性能,包括:(1)以共轭聚合物/C60或C60衍生物的主体异介质为光敏层,(2)分子水平上的主体异介质:D-A双功能聚合物,(3)单纯以富勒烯稠合体为光敏层,以及国内外这三种太阳能电池研究的进展情况及存在的问题.     

Synthesis and the Crystal Structure of a New Chiral 1D Metal–Organic Coordination Polymer Based on L-Prolineamide-Substituted Diarylacetylenedicarboxylic Acid Derivative

The new homochiral 1D metal–organic coordination polymer [Cu₂(EDPB)•H₂O]_n was synthesized starting from the original 3,3′-ethyne-1,2-diylbis[6-(L-prolylamino)benzoic acid] (H₄EDPB). The unique crystal structure of the new compound was established by powder X-ray diffraction. The [Cu₂(EDPB)•H₂O]_n system shows catalytic activity and enantioselectivity in a Henry reaction of p-nitrobenzaldehyde with nitromethane.     

还原聚苯胺插层氧化石墨纳米材料修饰电极用于抗坏血酸测定的研究

本文研制成还原聚苯胺插层氧化石墨纳米材料(R-(PAI/GO))修饰电极,并用于测定抗坏血酸(AA)。在pH5.02的Brinton-Robinson(B-R)缓冲溶液中,AA可在R-(PAI/GO)修饰电极上产生一对氧化还原峰,该峰的峰电流与AA浓度的对数在1.0×10-9~4.24×10-2mol/L范围呈良好的线性关系,相关系数为0.9910。多巴胺(DA)等物质对AA的测定无干扰。该电极制作简单,有良好的稳定性和重现性,用于实际试样中AA的测定,结果满意。