The microstructure of di-alkyl chain cationic/nonionic surfactant mixtures: observation of coexisting lamellar and micellar phases and depletion induced phase separation.
The microstructure of di-alkyl chain cationic/nonionic surfactant mixtures: observation of coexisting lamellar and micellar phases and depletion induced phase separation.
复制标题
二烷基链阳离子/非离子表面活性剂混合物的微观结构：共存的层状和胶束相以及耗尽诱导的相分离的观察。
DOI：
10.1021/jp0500788
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
H. Buron
中科院分区：
文献类型：
--
作者：
J. Penfold;E. Staples;S. Ugazio;I. Tucker;L. Soubiran;J. Hubbard;M. Noro;B. O'Malley;A. Ferrante;G. Ford;H. Buron
采用小角中子散射技术对二烷基链阳离子/非离子表面活性剂混合物水溶液中微观结构和组成的演变进行了详细研究。对于所研究的所有体系，我们观察到从主要的层状相，对于富含二烷基链阳离子表面活性剂的溶液，到混合的阳离子/非离子胶束，对于富含非离子表面活性剂的溶液。在中间的溶液组成中，存在片层相和胶束相共存的区域，其相对量随溶液组成的变化而变化。研究了几种不同的二烷基链阳离子表面活性剂DHDAB、2HT、DHTAC、DHTA硫酸甲酯和DISDA硫酸甲酯，以及非离子表面活性剂C12E12和C12E23。讨论了这些体系相行为的差异，并对DHDAB/C12E12混合物的相行为与理论预测进行了直接比较。结果表明，胶束组分的耗散力是导致这些混合体系相分离的主要因素，胶束的大小和体积分数是关键因素。
The evolution of the microstructure and composition occurring in the aqueous solutions of di-alkyl chain cationic/nonionic surfactant mixtures has been studied in detail using small angle neutron scattering, SANS. For all the systems studied we observe an evolution from a predominantly lamellar phase, for solutions rich in di-alkyl chain cationic surfactant, to mixed cationic/nonionic micelles, for solutions rich in the nonionic surfactant. At intermediate solution compositions there is a region of coexistence of lamellar and micellar phases, where the relative amounts change with solution composition. A number of different di-alkyl chain cationic surfactants, DHDAB, 2HT, DHTAC, DHTA methyl sulfate, and DISDA methyl sulfate, and nonionic surfactants, C12E12 and C12E23, are investigated. For these systems the differences in phase behavior is discussed, and for the mixture DHDAB/C12E12 a direct comparison with theoretical predictions of phase behavior is made. It is shown that the phase separation that can occur in these mixed systems is induced by a depletion force arising from the micellar component, and that the size and volume fraction of the micelles are critical factors.