Edlund H, Bydén M, Lindström B, Khan A
Department of Chemistry and Process Technology, Mid Sweden University, Sundsvall, S-851 70, Sweden
J Colloid Interface Sci. 1997 Dec 15;196(2):231-240. doi: 10.1006/jcis.1997.5206.
The isothermal ternary phase diagram for the 1-dodecylpyridinium bromide (1-DPB)-water-dodecanol system was determined at 40 degreesC, using 2H NMR, polarizing microscopy, and SAXS methods. All of the phases were characterized, and their ranges of existence were determined. The surfactant is easy to dissolve in water, yielding a normal micellar solution phase. After the normal micellar phase, on the binary surfactant-water axis, a normal hexagonal liquid crystalline phase is found at higher surfactant concentrations. On addition of dodecanol, four more phases are formed, i.e. a cubic, a lamellar, and a reverse hexagonal phase, followed by a reverse micellar solution phase. The lamellar liquid crystalline phase dominates the ternary phase diagram. The structures of the liquid crystalline phases were further examined using SAXS measurements, and the results are discussed in terms of the critical packing parameter, cpp, and electrostatic forces. The SAXS experiments show a pronounced swelling of the rods in the hexagonal phase, from 28.5 to 33 Å on addition of dodecanol, whereas the cylindrical aqueous core of the reverse hexagonal phase has a diameter of 18-21 Å, depending on sample composition. The average bilayer thickness of the lamellar phase is about 24 Å. Copyright 1997 Academic Press.
使用2H NMR、偏光显微镜和小角X射线散射（SAXS）方法，在40℃下测定了溴化1-十二烷基吡啶鎓（1-DPB）-水-十二烷醇体系的等温三元相图。对所有相进行了表征，并确定了它们的存在范围。该表面活性剂易于溶于水，形成正常的胶束溶液相。在正常胶束相之后，在二元表面活性剂-水轴上，在较高的表面活性剂浓度下发现一个正常的六方液晶相。加入十二烷醇后，又形成了另外四个相，即立方相、层状相和反六方相，随后是反胶束溶液相。层状液晶相在三元相图中占主导地位。使用SAXS测量进一步研究了液晶相的结构，并根据临界堆积参数cpp和静电力对结果进行了讨论。SAXS实验表明，在六方相中，棒状结构明显膨胀，加入十二烷醇后从28.5 Å膨胀到33 Å，而反六方相的圆柱形水核直径为18 - 21 Å，这取决于样品组成。层状相的平均双层厚度约为24 Å。版权所有1997年学术出版社。
