Specific ion effects on the micellization of aqueous mixed cationic/anionic surfactant systems with various counterions
Specific ion effects on the micellization of aqueous mixed cationic/anionic surfactant systems with various counterions
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特定离子对具有各种抗衡离子的水性混合阳离子/阴离子表面活性剂体系的胶束化的影响
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Yan-Qing Nan
中科院分区：
文献类型：
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作者：
Li-Sheng Hao;Ni Yang;Guang-Yu Xu;Yun-Feng Jia;Qian Liu;Yan-Qing Nan
研究了阳离子Gemini表面活性剂[C12H25(CH3)2N(CH2)3N(CH3)2C12H25]X2与阳离子表面活性剂[C12H25(CH3)2N(CH2)3N(CH3)2C12H25]X2，其中X−=F−，Cl−，Br−，Ac−，NO3−与阴离子表面活性剂十二烷基磺酸盐C12H25SO3Y，Y+=Na+，K+，Rb+在水溶液中的胶束化。还研究了一些12-3-122+·2X−/Y+As−/H2O体系的混合胶束作用。对于单离子表面活性剂，临界胶束浓度(CMC)按Hofmeister顺序递减，表面活性剂离子与相应离子形成离子对的能力较强，胶束自组装能力较强，CMC较小。对于12-3-122+·2X−/Y+As−/H_2O体系，令人惊讶的是，不同组成的12-3-−/Na+As−/H_2O体系的临界胶束浓度远大于相同组成的12-3-122+·2X−/Y+As−/H_2O体系的临界胶束浓度。与单一离子表面活性剂明显不同的是，如果反离子X-−和Y+之间存在较弱的离子对形成能力，表面活性剂离子与相应的反离子之间较强的离子对形成能力可以提高12-3-12 2+·2X−/Y+As−/H2O体系的临界胶束浓度。用离解Margules模型对混合的CMC值进行了关联，并与数据进行了很好的拟合。模型参数A12和A21可以用来衡量12-3-122+·2X−和Y+As−之间的协同作用，它们反映了二体和三体吸引相互作用，以及由于反离子X−和Y+的特殊离子效应而产生的相互作用差异。
The micellization of cationic gemini surfactants with various counterions,[C12H25(CH3)2N(CH2)3N(CH3)2C12H25]X2, designated as 12-3-122+·2X−, with X−= F−, Cl−, Br−, Ac−,and NO3−, and anionic conventional surfactants alkali dodecylsulfonates with various counterionsC12H25SO3Y, designated as Y+AS−, with Y+= Na+, K+, Rb+in aqueous solutions has been investigated. Themixed micellization of some 12-3-122+·2X−/Y+AS−/H2O systems has also been investigated. For the singleionic surfactants, the critical micelle concentration (cmc) decreases in the Hofmeister sequence of thecounterions, strong formation ability of ion pairs between surfactant ions and the corresponding coun-terions leads to strong micelle self-assembly ability and small cmc. For the 12-3-122+·2X−/Y+AS−/H2Osystems, to our surprise, the cmc values of the 12-3-122+·2NO3−/Na+AS−/H2O systems with differentcompositions are much larger than those of the other 12-3-122+·2X−/Y+AS−/H2O systems with the samecompositions. Significantly different from the single ionic surfactants, if there is weak formation abilityof ion pairs between counterions X−and Y+, strong formation ability of ion pairs between surfactant ionsand the corresponding counterions may increase the cmc for 12-3-122+·2X−/Y+AS−/H2O system. Thedissociated Margules model has been used to correlate the mixed cmc values and fits the data well. Themodel parameters A12and A21can be used as measure of synergism between 12-3-122+·2X−and Y+AS−,and they reflect the two-body and three-body attractive interactions, and the interaction differencesdue to the specific ion effect of counterions X−and Y+.