Phase behavior of poly(oxyethylene) cholesteryl ether/novel alkanolamide/water systems.
Phase behavior of poly(oxyethylene) cholesteryl ether/novel alkanolamide/water systems.
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DOI：
10.1016/j.jcis.2004.04.062
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发表时间：
2004-09
影响因子：
9.9
通讯作者：
Md. Khalid Hossain;Durga P. Acharya;T. Sakai;H. Kunieda
中科院分区：
文献类型：
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作者：
Md. Khalid Hossain;Durga P. Acharya;T. Sakai;H. Kunieda
采用目视观察和x射线小角散射的方法，在25℃条件下研究了聚氧乙烯胆甾醇醚（ChEOn, n=15和10）、新型烷醇酰胺型泡沫助剂、十二烷基n -甲基乙醇酰胺（NMEA-12）和水的混合非离子表面活性剂体系的相行为和微观结构。在ChEO15/水二元体系中，随着表面活性剂浓度的增加，依次形成水胶束相（Wm）、不连续立方液晶相（I1）、六边形相（H1）、矩形带状相（R1）、层状相（Lα）和固相(S)。尽管在常规表面活性剂体系中，r1相是一个在很窄的组成范围内形成的中间相，但它的结构域比H1的结构域要宽得多，这可能是由于聚集体亲脂核心中大块的胆甾基团造成的堆积约束。在ChEO15/水二元体系中加入亲脂性NMEA-12后，聚集体的界面曲率减小，在二元体系中形成的胶束或液晶相通过存在于较宽浓度范围内的l α相转变为相反的胶束（Om）相。SAXS结果建立了r1相的（11）面与l α相的（10）面之间的外延关系。ChEO10/NMEA-12/水体系的相图大体相似，不同之处是Wmto r1的相变是通过一个结构未知的光学各向异性液晶相进行的，而r1到l α的相变是通过一个狭窄的中间缺陷层状（LHα）相进行的。还讨论了在ChEOn/NMEA-12/water体系中形成的聚合体大小和形状以及r1相的单位胞的变化。
The phase behavior and microstructure of mixed nonionic surfactant systems containing poly(oxyethylene) cholesteryl ether (ChEOn, n=15 and 10), a new alkanolamide-type foam booster, dodecanoyl N-methylethanolamide (NMEA-12), and water, were investigated at 25°C by means of visual observation and small-angle X-ray scattering. In the ChEO15/water binary system, aqueous micellar (Wm), discontinuous cubic liquid crystal (I1), hexagonal (H1), rectangular ribbon (R1), lamellar (Lα), and solid (S) phases are successively formed with increasing surfactant concentration. Although the R1phase is an intermediate phase formed in a very narrow composition range in conventional surfactant systems, its domain is unusually wider than that of H1, which may be attributed to the packing constraint caused by the bulky cholesteric group in the lipophilic core of the aggregate. Upon addition of lipophilic NMEA-12 to the ChEO15/water binary system, the interfacial curvature of the aggregates decreases, and the micellar or liquid crystal phases formed in the binary system transform to the reverse micellar (Om) phase via the Lαphase existing over a wide concentration range. The SAXS results establish an epitaxial relationship between the (11) plane of the R1phase and the (10) plane of the Lαphase. The ChEO10/NMEA-12/water system shows a phase diagram of similar general appearance, except that the Wmto R1phase transformation occurs via an optically anisotropic liquid crystal phase of unknown structure and the R1to Lαphase transition occurs through a narrow intermediate defected lamellar (LHα) phase. The variation in the aggregate size and shape and the unit cell of the R1phase formed in ChEOn/NMEA-12/water systems is also discussed.