Rojas Mario R, Müller Alejandro J, Sáez A Eduardo
Grupo de Polímeros USB, Departamento de Ciencias de los Materiales, Universidad Simón Bolívar, Apartado 89000, Caracas 1080-A, Venezuela.
J Colloid Interface Sci. 2008 Oct 1;326(1):221-6. doi: 10.1016/j.jcis.2008.07.022. Epub 2008 Jul 18.
The rheology of solutions of wormlike micelles formed by oppositely charged surfactant mixtures (cationic cetyl trimethylammonium p-toluene sulfonate, CTAT, and anionic sodium dodecyl sulfate, SDS), in the dilute and semi-dilute regimes, were studied under simple shear and porous media flows. Aqueous mixtures of CTAT and SDS formed homogeneous solutions for SDS/CTAT molar ratios below 0.12. Solutions of mixtures exhibited a strong synergistic effect in shear viscosity, especially in the semi-dilute regime with respect to wormlike micelles, reaching a four order of magnitude increase in the zero-shear rate viscosity for solutions with 20 mM CTAT. Oscillatory shear results demonstrated that the microstructure of CTAT wormlike micelles is sensitive to SDS addition. The cross-over relaxation times of wormlike micelles of 20 mM CTAT solutions increased by three orders of magnitude with the addition of up to 2 mM of SDS, and the solutions became increasingly elastic. The shear thickening process observed in shear rheology became more pronounced in porous media flow due to the formation of stronger cooperative structures induced by the extensional component of the flow.
研究了由带相反电荷的表面活性剂混合物（阳离子十六烷基三甲基对甲苯磺酸盐，CTAT，和阴离子十二烷基硫酸钠，SDS）形成的蠕虫状胶束溶液在稀溶液和半稀溶液状态下，在简单剪切流和多孔介质流中的流变学性质。对于SDS/CTAT摩尔比低于0.12的情况，CTAT和SDS的水性混合物形成均匀溶液。混合物溶液在剪切粘度方面表现出强烈的协同效应，特别是对于蠕虫状胶束而言在半稀溶液状态下，对于含有20 mM CTAT的溶液，零剪切速率粘度增加了四个数量级。振荡剪切结果表明，CTAT蠕虫状胶束的微观结构对SDS的添加敏感。添加高达2 mM的SDS后，20 mM CTAT溶液的蠕虫状胶束的交叉弛豫时间增加了三个数量级，并且溶液的弹性越来越大。由于流动的拉伸分量诱导形成更强的协同结构，在多孔介质流中，剪切流变学中观察到的剪切增稠过程变得更加明显。
