摘要
用偶氮聚电解质上的偶氮苯基团作为“探针”,研究了侧链偶氮聚电解质聚{丙烯酸2[4(4′乙氧基苯基偶氮)苯氧基]乙酯co丙烯酸}(PEAPE)在水中的H聚集及其对光响应性的影响.研究发现,与在DMF溶液的紫外吸收光谱相比,偶氮聚电解质在水中的紫外吸收λmax发生明显蓝移,表明在水溶液中偶氮生色团形成了H聚集体.溶解在DMF H_(2)O混合溶剂中的上述偶氮聚电解质也存在部分H聚集,H聚集程度与水和DMF的比例有关.H聚集体的形成使光异构化速率明显减慢,异构化效率显著降低.同时,其光异构化动力学不符合一级指数衰减规律,说明该过程同时包含‘孤立的’偶氮生色团的光异构化反应和H-聚集体的光致解聚集.
By using spectroscopic characteristics of azo chromophores in different states as a'probe',H-aggregation of the azo chromospheres of a polyelectrolyte poly{2-[4-(4'-ethoxyphenylazo)phenoxy]ethyl acrylate-co-acrylic acid}(PEAPE)aqueous solutions and its effect on photo-responsive behavior were studied.Compared with the azo polyelectrolytes in DMF,PEAPE in H2O showed an obvious blue-shift of the maximum absorbance due to Haggregation of the azo chromophores formed in the solution.There also exists H-aggregation of the azo chromospheres in PEAPE solution in DMF/H2O,and the degree of H-aggregation depends on the ratio of DMF and H_(2)O.The UVV is spectra of PEAPE aqueous solution change with different degrees of functionalization of the azo chromophores.With the degree of functionalization increase,the lambda(max)of PEAPE gradually blue shifts,which suggests the degree of H-aggregation increase.H-Aggregation of the azo chromospheres results in a slower photo-isomerization rate and lower photo-isomerization efficiency of the azo polyelectrolyte PEAPE.The photo-isomerization kinetics of the PEAPE aqueous solution doesn't obey the first order exponential decay function,which also indicates that the coexistence of H-aggregates and'isolated'azo chromospheres in the system.
作者
邓永红
王晓工
DENG Yonghong;WANG Xiaogong(Department of Chemical Engineering,School of Materials Science and Engineering,Tsinghua University,Beijing 100084)
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2003年第5期704-708,共5页
Acta Polymerica Sinica
基金
国家自然科学基金资助项目(基金号59925309)
关键词
偶氮聚电解质
H-聚集
光响应
顺反异构
azo polyelectrolyte
H-aggregation
photo-responsive
isomerization
