Abstract

The effect of the concentration and of the composition of mixtures of a traditional surfactant sodium dodecyl sulphate (SDS) and of linalool (LL), a volatile fragrance with surface-active properties, on the surface tension of their aqueous solutions has been studied. Surface tension was measured both under equilibrium and under dynamic conditions of the surface formation (in a time range of 20 ms to 20 s), as well as during evaporation of solutions. It has been shown that under equilibrium conditions the individual surfactants and their mixtures exhibit similar surface activity. On the contrary, under dynamic conditions LL decreases surface tension faster in comparison to SDS, so that the surface tension of mixed solutions is determined by adsorption of LL. A synergetic effect on the decreasing of the surface tension at high surfactants concentration is observed both under dynamic and under equilibrium conditions. Upon evaporation of droplets of mixed solutions at a time interval of about minutes, the composition of the adsorption layer changes as a result of desorption of LL into the gas phase, so that the surface tension is determined by the adsorption of the second component—SDS.

中文翻译：

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平衡和动态条件下十二烷基硫酸钠和芳樟醇混合物水溶液的表面性能

摘要

研究了传统表面活性剂十二烷基硫酸钠（SDS）和芳樟醇（LL）（一种具有表面活性的挥发性香料）的浓度和组成对它们水溶液的表面张力的影响。在表面形成的平衡条件和动态条件下（在20 ms至20 s的时间范围内）以及在溶液蒸发过程中都测量了表面张力。已经表明，在平衡条件下，各个表面活性剂及其混合物表现出相似的表面活性。相反，在动态条件下，与SDS相比，LL降低表面张力的速度更快，因此混合溶液的表面张力取决于LL的吸附。在动态和平衡条件下均观察到在高表面活性剂浓度下对降低表面张力的协同作用。当混合溶液的液滴以大约几分钟的时间间隔蒸发时，由于LL解吸到气相中，吸附层的成分发生了变化，因此表面张力取决于第二种组分SDS的吸附。