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

已知嵌段共聚物在对嵌段之一具有选择性的溶剂中形成胶束（聚合物胶束）。由于胶束具有不同于常规洗涤剂胶束的特性，人们对其进行了大量的研究。本研究揭示了聚合物胶束作为能量传递等物理和光化学过程的反应场的特性。使用的嵌段共聚物是Pluronic F68（EO_<78>PO_<30>EO_<78>）和Pluronic L64（EO_<13>PO_<30>EO_<13>）。研究结果如下：1.研究了罗丹明B（供体）与孔雀石绿绿色（受体）之间的电子能量转移。随着胶束的形成，能量传递被大大抑制。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。结果表明，胶束经历了一个大的构象变化，从一个膨胀到一个收缩的结构，随着温度的增加和Pluronics的临界胶束浓度（CMC的）是强烈依赖于温度的常规洗涤剂相反。的普朗尼克胶束的微粘度估计从偏振度和荧光寿命。还测定了Pluronics的CMC。

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.