端基对侧链型偶氮聚电解质自组装膜内生色团取向的影响

用偏振紫外光谱研究了 4种带有不同端基的侧链型偶氮聚电解质静电逐层自组装膜中偶氮生色团的初始取向 .讨论了不同的端基对偶氮生色团在自组装膜中初始取向的影响 .进一步探讨了偶氮聚电解质自组装膜的结构特点 .研究表明 ,侧链型偶氮聚电解质自组装膜中偶氮生色团普遍存在一定程度的沿面取向 .偶氮生色团所带端基的类型对其在自组装膜中的取向程度有较大的影响 ,这主要取决于偶氮生色团与聚阳离子基底的电荷相互作用和极性相互作用等 .对偶氮生色团在水溶液中能形成H 聚集体的自组装膜来说 ,H 聚集体对生色团取向也有一定的影响 .结果表明 ,在制备需控制生色团取向性的自组装膜时 ,要考虑生色团上的不同端基对取向的影响

SUBSTITUENT EFFECT ON ORIENTATION OF CHROMOPHORES IN SELF-ASSEMBLED MULTILAYERS OF SIDE-CHAIN AZO POLYELECTROLYTES

Orientation of azo chromophores in electrostatic self-assembled multilayer films of four side-chain azo polyelectrolytes that contain azobenzene derivatives with different p-substituents was investigated by using polarized UV-Vis absorption spectroscopy.Influences of substituents on the orientation of the azo chromophores were discussed in detail.The structural characteristics of these self-assembled films were further investigated.It was found that the homogeneous orientation tendency of azobenzene was a common phenomenon in the self-assembled films fabricated by electrostatic layer-by-layer dipping process of the side-chain azo polyelectrolytes and poly(diallyldimethyl ammonium chloride); substituents that link to azobenzene have influences on the orientation of azobenzene in self-assembled films,which could be attributed to charge interaction and dipolar interaction between the chromophores and the polycation substrates.For those self-assembled multilayers with H-aggregation, the effect of substituents on the orientation of azobenzene was also influenced by the H-aggregation.The results indicate that the orientation of azobenzene in self-assembled films can be effectively adjusted by selecting polyelectrolytes containing azobenzenes with different p-substituents.