Penfold J, Staples E, Ugazio S, Tucker I, Soubiran L, Hubbard J, Noro M, O'Malley B, Ferrante A, Ford G, Buron H
ISIS Facility, CCLRC, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK.
J Phys Chem B. 2005 Sep 29;109(38):18107-16. doi: 10.1021/jp0500788.
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.
利用小角中子散射（SANS）对二烷基链阳离子/非离子表面活性剂混合物水溶液中发生的微观结构和组成演变进行了详细研究。对于所有研究的体系，我们观察到从富含二烷基链阳离子表面活性剂的溶液中的主要层状相，演变为富含非离子表面活性剂的溶液中的混合阳离子/非离子胶束。在中间溶液组成处，存在层状相和胶束相共存的区域，其中相对含量随溶液组成而变化。研究了多种不同的二烷基链阳离子表面活性剂，如二己基二甲基溴化铵（DHDAB）、2-己基-1-十二烷基三甲基氯化铵（2HT）、二己基二甲基氯化铵（DHTAC）、二己基二甲基硫酸甲酯（DHTA甲基硫酸盐）和二异辛基二甲基硫酸甲酯（DISDA甲基硫酸盐），以及非离子表面活性剂，如十二烷基聚氧乙烯醚（C12E12）和十二烷基聚氧乙烯醚（C12E23）。讨论了这些体系在相行为上的差异，并对DHDAB/C12E12混合物与相行为的理论预测进行了直接比较。结果表明，这些混合体系中可能发生的相分离是由胶束组分产生的排空力引起的，并且胶束的尺寸和体积分数是关键因素。
