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Molecular Level Study of Intra- and Inter-Particle Intractions in Polyelectrolyte Nanogel Systems

聚电解质纳米凝胶系统中颗粒内和颗粒间相互作用的分子水平研究

基本信息

批准号：
15350127
负责人：
KOKUFUTA Etsuo
金额：
$ 9.28万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

This research project aims to elucidate at the molecular level the nature of volume-phase transitions in polyelectrolyte gels. Our experimental strategy is to measure the dimensional changes in polyelectrolyte nanoparticles with and without cross-links and to compare these with the volume change of polyelectrolyte bulk gels with the same chemical compositions. We have synthesized and used both cross-linked and linear polymers based on N-isopropylacrylamide, to which anions and cations as well as both (ampholytes) were bound via copolymerizations or terpolymerizations. Static light scattering, dynamic light scattering and electrophoretic light scattering were employed to study the following subjects : (i)Effects of pH, temperature and ionic strength on the hydrodynamic radius and radius gyration of cross-linked polyelectrolyte nanoparticles (nanogels) and on their electrophoretic mobilities as an indication of net charges of polyelectrolytes. (ii)Comparison of the results obtained in (i … More )with those of linear polyelectrolytes as an analog of the nanogels. (iii)Complex formation of polyelectrolyte nanogels with linear polyions whose charges are opposite each other (polymer-particle interactions in charged colloidal systems). (iv)Complex formation between oppositely charged nanogel particles (particle-particle interactions in charged colloidal systems). In addition, we studied the complex formation of neutral polymers with proteins with the intention of synthesis of a novel ionic nanogel in which globular multipartial charges (i.e., proteins) are in a "cage" of neutral polymer network (i.e., ionic nanogels with entrapped protein charges). It has become apparent that all of the results obtained from the present study can be well accounted for in terms of our balance model [(a)Ilmain, F. ; Tanaka, T. ; Kokufuta, E. Nature 1991,349,400 ; (b)Kokufuta, E. In : Physical Chemistry of Polyelectrolytes ; Radeva, T., Ed. ; Marcel Dekker, Inc., New York, Basel,2000;Chapter 17] ; that is, the volume phase transition in gels can be determined by hypothesizing a balance between the repulsion and attraction among functional groups attached to the network-When a repulsive force, usually electrostatic in nature, overcomes an attractive force, the gel undergoes a swelling change ; hydrogen bonding and hydrophobic interaction, other than the usual electrostatic attraction, are considered as the attractive force. As result, the present research strongly supports the balance model, then we have started a new project in which the balance model is allowing the design of ionic nanogels whose responsive performance is the same as observed in the corresponding graft or block copolymers. Less

本研究项目旨在从分子水平上阐明凝胶中体积相变的性质。我们的实验策略是测量具有和不具有交联的纳米颗粒的尺寸变化，并将这些与具有相同化学组成的纳米颗粒散装凝胶的体积变化进行比较。我们已经合成并使用了基于N-异丙基丙烯酰胺的交联和线性聚合物，阴离子和阳离子以及两者（两性电解质）通过共聚或三元共聚结合到该聚合物上。采用静态光散射、动态光散射和电泳光散射研究了以下主题：（i）pH、温度和离子强度对交联纳米粒子（纳米凝胶）的流体动力学半径和回转半径以及作为聚电解质净电荷指示的电泳迁移率的影响。（二）比较（一）中的结果 ...更多信息）与作为纳米凝胶类似物的线性聚电解质的那些相比。（iii）纳米凝胶与线性聚离子的复合物形成，所述线性聚离子的电荷彼此相反（带电胶体系统中的聚合物-颗粒相互作用）。（iv）带相反电荷的纳米凝胶颗粒之间的复合物形成（带电胶体系统中的颗粒-颗粒相互作用）。此外，我们研究了中性聚合物与蛋白质的复合物形成，目的是合成一种新型离子纳米凝胶，其中球状多部分电荷（即，蛋白质）处于中性聚合物网络的“笼”中（即，具有捕获的蛋白质电荷的离子纳米凝胶）。很明显，从本研究中获得的所有结果都可以很好地解释我们的平衡模型[（a）Ilmain，F。; Tanaka，T. ; Kokufuta，E.（B）Kokufuta，E.在：聚电解质的物理化学; Radeva，T.，编辑; Marcel Dekker，Inc.，纽约，巴塞尔，2000;第17章] ;也就是说，凝胶中的体积相变可以通过假设连接到网络的官能团之间的排斥和吸引之间的平衡来确定-当排斥力（通常是静电性质的）克服吸引力时，凝胶经历溶胀变化;氢键和疏水相互作用，而不是通常的静电吸引，被认为是吸引力。因此，目前的研究强烈支持平衡模型，然后我们已经开始了一个新的项目，其中平衡模型允许设计离子纳米凝胶，其响应性能与在相应的接枝或嵌段共聚物中观察到的相同。少