Staples E, Thompson L, Tucker I, Penfold J, Thomas RK, Lu JR
Port Sunlight Laboratory, Unilever Research, Quarry Road East, Bebington, Wirral, United Kingdom
J Colloid Interface Sci. 1996 Dec 25;184(2):391-8. doi: 10.1006/jcis.1996.0633.
Neutron reflection and surface tension have been used to study the adsorption of the nonionic surfactant monododecyl hexaethylene glycol (C12E6) and the mixed nonionic-anionic surfactants n-dodecyl triethylene glycol (C12E3) and Sodium dodecyl sulfate (SDS) at the air-liquid interface. Water and a sorbitol (d-glucitol, CH2OH(HCOH)4CH2OH)/water mixture were selected as the solvents. The addition of 300 g/liter of sorbitol to an aqueous solution of C12E6 reduces the critical micellar concentration, cmc, from approximately 7 x 10(-5) to approximately 3 x 10(-5) M, and increases the surface pressure at the cmc; the effect on the C12E3/SDS mixture is less. Despite these changes, the pattern of adsorption at the air-liquid interface is essentially unaltered by the addition of sorbitol, and the surface tension and neutron reflectivity data are in good agreement. The consequences of the sorbitol addition are however seen directly in the structure of the C12E6 monolayer. The ethylene oxide (EO) chain is more extended than in water, and more displaced from the solvent, consistent with dehydration of the ethylene oxide group.
中子反射和表面张力已被用于研究非离子表面活性剂单十二烷基六乙二醇（C12E6）以及非离子 - 阴离子混合表面活性剂正十二烷基三乙二醇（C12E3）和十二烷基硫酸钠（SDS）在气 - 液界面的吸附情况。选择水和山梨醇（d - 葡萄糖醇，CH2OH(HCOH)4CH2OH）/水混合物作为溶剂。向C12E6水溶液中添加300克/升山梨醇可使临界胶束浓度cmc从约7×10^(-5)降至约3×10^(-5) M，并增加cmc时的表面压力；对C12E3/SDS混合物的影响较小。尽管有这些变化，但添加山梨醇后气 - 液界面的吸附模式基本未改变，则表面张力和中子反射率数据吻合良好。然而，添加山梨醇的影响直接体现在C12E6单分子层的结构中。环氧乙烷（EO）链比在水中伸展得更多，并且从溶剂中位移得更多，这与环氧乙烷基团的脱水情况一致。
