Halogen-free alkyl sulfate-based surface active ionic liquids (SAILs),1-butyl-3-methylimidazolium alkyl sulfate { [C4mim] [CnH2n+1SO4] (n =8,12,16) },were synthesized through ion exchange reaction.The aggregation behaviors of synthesized SAILs in aqueous solution were investigated by surface tension,static fluorescence and static fluorescence quenching measurements.The results showed that the ionic liquid surfactants with organic imidazole cation([C4mim] +) as counter ions have higher surface activity compared to that surfactants with traditional inorganic counter ions.The effect of inhibiting molecular ordered arrangement derived from the existence of hydrogen bonding produced by [C4mim] + is less than the hydrophobic effect that can promote molecular ordered arrangement.The anions with long alkyl chains are the major components of interracial film and micelles.The increase of anionic alkyl chain length promotes the formation of micelles but inhibits the participation of [C4 mim] + to the formation of interface or micelles in some degree.The longer the anionic alkyl chain,the more unfavorable for the [C4mim] + to participate in the formation of interfacial film or micelles,which leads to the looser arrangement of surfactants in interfacial film or micelles.Correspondingly,the interfacial tension is higher and the micellar aggregation number is smaller.%采用离子交换法,由氯化1-丁基-3-甲基咪唑鎓(C4mimCl)和烷基硫酸钠合成了一系列无卤素的阴离子表面活性离子液体一烷基硫酸1-丁基-3-甲基咪唑鎓盐[C4mim][CnH2n+1SO4](n=8,12,16),利用表面张力仪、稳态荧光光谱等手段考察了表面活性离子液体在水溶液表面及体相中的聚集行为.结果表明,与传统无机反离子相比,有机咪唑阳离子[C4mim]+作为反离子的离子液体型表面活性剂具有较高的表面活性,[C4mim]+产生的氢键引起的抑制分子规则排列的作用小于其促进分子有序排列的疏水作用.长烷基链的阴离子是界面膜及胶束的主要组成成分,阴离子疏水烷基碳链的增长虽然可促进胶束的形成,但却在一定程度上抑制[C4mim]+参与界面或胶束的形成;阴离子所带烷基链越长,越不利于阳离子[C4mim]+参与界面膜或胶束的形成,界面膜或胶束中表面活性剂排布越松散,即界面张力越大,体系中胶束聚集数较小.
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