Department of Chemistry, Harvey Mudd College, Claremont, CA 91711, USA.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Apr;75(4):1354-61. doi: 10.1016/j.saa.2009.12.087. Epub 2010 Jan 11.
The UV-vis absorption properties of azo dyes are known to exhibit a variation with the polarity and acidity of the dye environment. The spectral properties of a series of anionic azo dyes were characterized to further probe the interaction of these dyes with two types of surfactant aggregates: (1) the spherical micelles formed in aqueous solution by alkyltrimethylammonium bromide (C(n)TAB) surfactants with n=10-16 and (2) the unilamellar vesicles spontaneously formed in water from binary mixtures of the oppositely-charged double-tailed surfactants cationic didodecyldimethylammonium bromide (DDAB) and anionic sodium dioctylsulfosuccinate (Aerosol OT or AOT). The observed dye spectra reflect the solvatochromic behavior of the dyes and suggest the location and orientation of the dye within the surfactant aggregates. Deconvolution of the overall spectra into sums of Gaussian curves more readily displays any contributions of tautomeric forms of the azo dyes resulting from intramolecular hydrogen bonding. The rich variation in UV/vis absorption properties of these anionic azo dyes supports their use as sensitive tools to explore the nanostructures of surfactant aggregates.
偶氮染料的紫外-可见吸收特性已知随染料环境的极性和酸度而变化。研究了一系列阴离子偶氮染料的光谱特性，以进一步探究这些染料与两种类型的表面活性剂聚集体的相互作用：（1）由烷基三甲基溴化铵（C(n)TAB）表面活性剂在水溶液中形成的球形胶束，其中 n=10-16；（2）由带相反电荷的双尾表面活性剂阳离子双十二烷基二甲基溴化铵（DDAB）和阴离子二辛基磺基琥珀酸钠（Aerosol OT 或 AOT）在水相中自发形成的单层囊泡。观察到的染料光谱反映了染料的溶剂化变色行为，并表明染料在表面活性剂聚集体中的位置和取向。将整体光谱分解为高斯曲线的和更容易显示出偶氮染料的互变异构形式对由于分子内氢键引起的贡献。这些阴离子偶氮染料的紫外-可见吸收特性的丰富变化支持将其用作探索表面活性剂聚集体纳米结构的敏感工具。
