Photo-isomerization of spiropyran-modified cationic surfactants
Photo-isomerization of spiropyran-modified cationic surfactants
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DOI：
10.1016/j.jcis.2007.08.042
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发表时间：
2007-12-15
影响因子：
9.9
通讯作者：
Abe, Masahiko
中科院分区：
文献类型：
--
作者：
Sakai, Hideki;Ebana, Hiroatsu;Abe, Masahiko
利用紫外-可见吸收光谱和表面张力数据，研究了一种新合成的表面活性剂1 '（6-三甲基铵基十二烷基）-3'，3 '-二甲基-6-硝基螺环-（2 H-1-苯并吡喃-2，2'-吲哚啉）溴化物（SP-Me-12）的光致异构化反应.可见光（λ> 420 nm）入射到SP-Me-12的水溶液上导致从汞（MC）形式到螺吡喃（SP）形式的异构化;这种结构变化通过MC形式的特征吸收峰的完全消失来证实。当表面活性剂溶液储存在黑暗中时，异构化的SP形式恢复到原始MC形式，然而，观察到的反向异构化速率比可见光照射所见的速率（从MC形式到SP形式）慢得多。对于光诱导的异构化，观察到表面活性剂水溶液的表面张力的可逆变化：在临界聚集浓度以下测量的表面张力由于可见光照射而降低，并且在黑暗中平衡期间逐渐逆转到原始水平。(C)2007年爱思唯尔公司All rights reserved.
Photo-induced isomerization of a newly synthesized surfactant,1'(6-trimethylammoniododecyl)-3',3'-dimethyl-6-nitrospiro-(2H-1-benzopyran-2,2'-indoline) bromide (SP-Me-12), has been characterized on the basis of the UV-vis absorption spectra and the surface tension data. Visible light (lambda > 420 nm) incident on the aqueous solution of SP-Me-12 results in the isomerization from the merocyanine (MC) form to the spiropyran (SP) form; this structural change was confirmed by a complete disappearance of a characteristic absorption peak of the MC form. When the surfactant solution is stored in the dark, the isomerized SP form reverts to the original MC form, however, the reverse isomerization rate is observed to be considerably slower than that seen for visible light irradiation (from the MC form to the SP form). A reversible change in the surface tension of the aqueous surfactant solution is observed for the photo-induced isomerization: the surface tension measured below the critical aggregation concentration decreases as a result of the visible light irradiation and it is gradually reversed to the original level during the equilibration in the dark. (C) 2007 Elsevier Inc. All rights reserved.