支化侧链偶氮聚电解质生色团H-聚集的动力学研究

CHROMOPHORE H-AGGREGATION KINETICS OF A BRANCHED SIDE-CHAIN AZO POLYELECTROLYTE

利用偶氮聚电解质上的偶氮苯基团作为“探针”,研究了支化侧链偶氮聚电解质PMAPB6P-AA的偶氮生色团H-聚集动力学过程.研究发现,在不同THF/H2O配比情况下,H-聚集的速率有很大差别,THF比例越小,生色团发生H-聚集的速率越大,即偶氮聚电解质在溶剂体系中的疏水聚集对发生H-聚集有重要推动作用.通过测定偶氮聚电解质上的“孤立”生色团和H-聚集体的紫外光谱最大吸收值变化,表征了H-聚集过程的动力学,并分别用一级和二级动力学方程进行了拟合.结果表明,偶氮聚电解质的H-聚集过程具有二级动力学过程的特点.

By using spectroscopic variation of azo chromophores in different states as a ＇probe＇, chromophore H- aggregation kinetics of a branched side-chain azo polyelectrolyte PMAPB6P-AA in THF/H20 solutions was studied. The THF/H2O ratio showed a significant effect on the H-aggregation rate. The H-aggregation rate increased as the H2O content increased. It indicates that the hydrophobic effect is an important driven force in the process of H- aggregation .The kinetic process of the H-aggregation was characterized by the change of the UV-Vis absorption ratios of the ＇isolated＇ azo chromophores and H-aggregates. Two kinds of kinetic equations were used to fit the H- aggregation process. The process can be well fitted by the second-order kinetic equation.