氧乙烯联接链的季铵盐Gemini表面活性剂合成及胶团化特性

合成了含氧乙烯联接链的季铵盐Gemini表面活性剂C12 2 En C12·2Br〔C12=C12H25N+(CH3)2,2=CH2CH2,En=(OC2H4)n,2Br=2Br-,n=1,2,3〕。以电导和稳态荧光法研究了胶团化行为,结果表明,C12 2 En C12·2Br的胶团化能力比其单体表面活性剂十二烷基三甲基溴化铵(C12TABr)高得多,接近于以2个亚甲基构成联接链的C12 2 C12·2Br。胶团聚集数N和表面反离子结合度K0也与C12 2 C12·2Br胶团相当。C12 2 En C12·2Br胶团化过程呈现焓/熵补偿现象,以n=1的胶团最为稳定。

Synthesis of Quaternary Ammonium Gemini Surfactants Containing Polyoxyethylene Spacer and Their Micellization in Aqueous Solution

The quaternary ammonium Gemini surfactants containing polyoxyethylene spacer, C_(12)-2-E_ n -C_(12)·2Br〔C_(12)=C_(12)H_(25)N~+(CH_3)_2,2=CH_2CH_2,E_ n =(OC_2H_4)_ n ,2Br=2Br~-, n =1,2,3〕,were synthesized and their micellization in aqueous solution was studied using conductivity and steady fluorescence measurements.The results showed that the ability of C_(12)-2-E_ n -C_(12)·2Br forming micelle is much stronger than that of the corresponding "monomer",dodecyltrimethylammonium bromide (C_(12)TABr).The value of CMC is close to that of C_(12)-2-C_(12)·2Br in which the spacer contains only two methylene groups.The aggregation number N and the degree of counterion association K _0 of C_(12)-2-E_ n -C_(12)·2Br and C_(12)-2-C_(12)·2Br micelles are also approximate to each other.The micellization of C_(12)-2-E_ n -C_(12)·2Br displays an entropy-driven character.In all systems the micelle formed by n =1 is the most stable.