Spectroscopic Studies on Photophysical and Photochemical Processes in Associated Water-soluble Polymers

相关水溶性聚合物中光物理和光化学过程的光谱研究

基本信息

批准号：
04640474
负责人：
NAKASHIMA Kenichi
金额：
$ 1.22万
依托单位：
Saga University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Block copolymers has been known to form micelles (polymer micelles) in a solvent selective for one of the blocks. Many investigations have been performed on the micelles because they have a variety of properties different from conventional detergent micelles. This study has been undertaken to reveal the characteristics of polymer micelles as a reaction field for photophysical and photochemical processes such as energy transfer. The block copolymers employed are Pluronic F68 (EO_<78>PO_<30>EO_<78>) and Pluronic L64 (EO_<13>PO_<30>EO_<13>). The results obtained are as follows :1.Electronic energy transfer from rhodamine B (donor) to malachite green (acceptor) are examined. The energy transfer is drastically suppressed as the micelles are formed. The decrease of energy transfer is ascribed to that the increase of microviscosity upon micellization dominates other factors such as concentration effect.2.The structures of Pluronic micelles are investigated by the use of rhodamine B and octadecylrhodamine B as fluorescent probes. It is revealed that the micelles undergo a large conformational change from a swollen to a shrunken structure as temperature is increased and that the critical micelle concentrations (CMC's) of the Pluronics are strongly depend on temperature in contrast to those of conventional detergents. Microviscosities of the Pluronic micelles are estimated from the degree of polarization and the fluorescence lifetimes. The CMC's of the Pluronics are also determined.

已知嵌段共聚物在对其中一种嵌段有选择性的溶剂中形成胶束（聚合物胶束）。由于胶束具有与传统洗涤剂胶束不同的多种特性，因此对其进行了许多研究。这项研究旨在揭示聚合物胶束作为光物理和光化学过程（例如能量转移）反应场的特性。所采用的嵌段共聚物是Pluronic F68(EO_<78>PO_<30>EO_<78>)和Pluronic L64(EO_<13>PO_<30>EO_<13>)。所得结果如下： 1.考察了罗丹明B(供体)到孔雀石绿(受体)的电子能量转移。当胶束形成时，能量转移被急剧抑制。能量转移的减少归因于胶束化时微粘度的增加主导了浓度效应等其他因素。2.以罗丹明B和十八烷基罗丹明B为荧光探针研究了Pluronic胶束的结构。研究表明，随着温度升高，胶束会经历从膨胀结构到收缩结构的巨大构象变化，并且与传统洗涤剂相比，Pluronics 的临界胶束浓度 (CMC) 强烈依赖于温度。 Pluronic 胶束的微观粘度是根据偏振度和荧光寿命估算的。 Pluronics 的 CMC 也已确定。