酯型双子阳离子表面活性剂与甲基橙的相互作用

Interactions between gemini cationic surfactants and methyl orange

通过紫外-可见光谱法研究了一系列具有不同疏水基的、含酯基双子季铵盐阳离子表面活性剂(EDC-1,2,3,4)与甲基橙(MO)之间的相互作用。结果表明,表面活性剂浓度在1 0×10-5mol·L-1左右时(远低于其cmc),EDC和MO聚集。这种聚集导致MO的紫外吸收光谱中π→π 吸收带蓝移98nm,即在365nm处形成一个新的吸收带。进一步增加EDC浓度至cmc以上时,由于MO增溶于EDC胶束内部,使λmax移至430nm处。并且分离出了EDC与MO聚集产生的聚合物,经1HNMR分析,其中EDC与MO的摩尔比为1∶2。

The interactions of methyl orange(MO)with a series of di(gemini)-cationic surfactants with ester bond(EDC)in aqueous solution were investigated by UV-vis spectroscopy.It is observed that the aggregation of the surfactant and MO takes place at surfactant concentrations far below the critical micelle concentration of the individual surfactants.The aggregation results in a ca.98 nm hypsochromic shift of the π?→π~* absorption band of MO.That is formation of a new absorption band of 365 nm.As the cencentration of EDC further increases to be higher than the cmc,due to the solubilization of MO in EDC micelle,λ_(max) shifts to 430 nm,and the complex formed by the aggregation of EDC and MO separates out.~1HNMR analysis shows that the molar ratio of EDC to MO is 1∶2.