Department of Interfacial Phenomena, Faculty of Chemistry, Institute of Chemical Sciences, Maria Curie-Skłodowska University in Lublin, 20-031 Lublin, Poland.
Molecules. 2022 Jun 3;27(11):3600. doi: 10.3390/molecules27113600.
The surface tension of aqueous solutions of Triton X-165 with rhamnolipid or surfactin mixtures was measured. The obtained results were applied for the determination of the concentration and composition of the Triton X-165 and biosurfactants mixture at the water-air interface as well as the contribution of the particular component of the mixtures to water surface tension reduction and the mutual influence of these components on the critical micelle concentration. The determination of these quantities was based on both the commonly used concepts and a new one proposed by us, which assumes that the composition of the mixed monolayer at the water-air interface depends directly on the pressure of the monolayer of the single mixture component and allows us to determine the surface concentration of each mixture component independently of surface tension isotherms shape. Taking into account the composition of the mixed monolayer at the water-air interface, the standard Gibbs adsorption free energy was considered. The obtained results allow us to state that the concentration of both mixture components corresponding to their saturated monolayer and the surface tension of their aqueous solution can be predicted using the surfactants' single monolayer pressure and their mole fraction in the mixed monolayer determined in the proposed way.
测定了含有鼠李糖脂或表面活性剂混合物的 Triton X-165 水溶液的表面张力。将获得的结果应用于确定水-气界面处 Triton X-165 和生物表面活性剂混合物的浓度和组成，以及混合物中特定成分对水表面张力降低的贡献以及这些成分对临界胶束浓度的相互影响。这些量的确定基于常用的概念和我们提出的新概念，该概念假设水-气界面混合单层的组成直接取决于单一混合物成分的单层压力，并允许我们独立于表面张力等温线的形状确定每个混合物成分的表面浓度。考虑到水-气界面混合单层的组成，还考虑了标准吉布斯吸附自由能。得到的结果表明，可以使用表面活性剂的单分子层压力及其在混合单层中的摩尔分数来预测对应于其饱和单分子层的混合物两种成分的浓度以及其水溶液的表面张力，这些分数是通过所提出的方法确定的。
