2种新型表面活性剂的物化性能研究

Study of Physichemical Properties of Zwitterionic Gemini Surfactants and Double-tail Sodium Alkylsulfate

以芘为荧光探针、二苯酮为猝灭剂,用荧光探针法测定了两性孪连表面活性剂和双尾阴离子表面活性剂的临界胶团浓度(cmc),探讨了盐对两性孪连和双尾阴离子表面活性剂的微极性的影响,用激光散射法、瞬态荧光法研究了表面活性剂的聚集性能。研究结果表明,稳态荧光探针法测得两性孪连表面活性剂的cmc比表面张力法的低,C10～16-C12的cmc在0.011～0.005mmol/L之间;烷基碳数增加,临界胶团浓度大幅度降低,胶团聚集数减小;双尾阴离子表面活性剂的胶团微极性随NaCl浓度增大而降低,而盐对两性表面活性剂的微极性影响小;瞬态荧光探针法测得两性表面活性剂在20cmc时的聚集数不足20,而采用激光散射法测定胶束的均方旋转半径为155.3nm,与文献值30nm～100μm囊泡的表述相符。

Critical micelle concentration (CMC) was determined by steady-state fluorescence probe method in which pyrene was used as fluorescence probe and benzophenone as quencher.Effect of NaCl on zwitterionic gemini and double-tail sodium alkylsulfate was studied.Aggregation performence of micelle of four zwitterionic gemini surfactants was determined by laser scattering and time-resolved fluorescence method.The experimental results show that CMC values are reduced with the increase of the hydrocarbon chain length of zwitterionic gemini surfactants.The CMC values determined by steady-state fluorescence are less than that of surface tension method.The micropolarity of anionic surfactants decreased with increase of concentration of NaCl,while micropolarity of zwitterionic geminis only changes a little.Evaluation of micelle performence of four zwitterionic geminis by laser scattering is more suitable than that of fluorescence method,with which aggregation number is no more than 20.