两亲嵌段共聚物溶液内胶束形成的温度效应

合成了一系列具有两亲嵌段结构的聚（乙二醇）（PEO）一聚（丙二醇）（PPO）共聚物．利用荧光探针及示差量热法测定了共聚物水溶液的临界胶束形成温度（CMT）值．发现二嵌段共聚物（PEO－PPO）和三嵌段共聚物（PEO－PPO－PEO）有着类似的变化规律，即随共聚物分子中疏水链（PPO）长度的增大，其CMT值降低．但三嵌段共聚（PPO－PEO－PPO）则因疏水链段处于共聚物分子的两端，因而在溶液中有可能形成立体网状交联结构．此外，利用探针分子在不同极性溶剂中荧光峰值波长发生位移的现象可以对形成胶束内核的组织程度、极性大小进行估测．

The Temperature Effect on Micellar Formation in the Amphiphilic Block Copolymer Solution

A series of poly (ethylene oxide) and poly(propylene oxide) block copolymers with amphiphilic structure have been synthesized in this paper. Both fluorescence probe and differential scanning calorimetric methods (DSC) were used to determine the critical micellar formation temperature(CMT) of these copolymers dissolved in water solution. It was found that the diblock copolymer (PEO-PPO) has almost the same properties as triblock (PEO-PPO-PEO) copolymer for which the CMT value decreases with the increasing of the length of hydrophobic segment in the molecule of copolymers. But, for another kind of triblock copolymer (PPO-PEO-PPO), its properties are completely different. It is probably due to the fact that the hydrophobic moieties are located at the terminal part of copolymeric chain which causes the solution to form a crosslinking network structure. In addition, by using of the peak wavelength shift phenomenon in fluorescence spectrum of probe compound which was dissolved in solvents with different polarities, the polarity and the degree of organization of internal nuclei in micelle can be evaluated.