Romero-Arias J Roberto, S Luviano Alberto, Costas Miguel, Hernández-Machado Aurora, Barrio Rafael A
Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, CdMx 01000, Mexico.
Laboratorio de Biofisicoquímica, Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, CdMx 04510, Mexico.
Soft Matter. 2021 Mar 11;17(9):2652-2658. doi: 10.1039/d0sm01796e.
A recent surface rheological study has shown that aqueous solutions of α-cyclodextrin (αCD) with anionic surfactants (S) display a remarkable viscoelasticity at the liquid/air interface, which has not been observed in similar systems. The dilatational modulus is various orders of magnitude larger than those for the binary mixtures αCD + water and S + water. The rheological response has been qualitatively related to the bulk distribution of species, the 2 : 1 inclusion complexes (αCD2 : S) playing a fundamental role. In this work, we have developed a model that considers dipole-dipole interactions between 2 : 1 inclusion complexes ordered on the liquid/air interface. When the model is applied to the specific experimental conditions, the dependencies on concentration and temperature of the dilatational modulus and the surface tension were found to be in excellent agreement with the data, indicating clearly that dipole-dipole interactions determine and control the rheological behavior of the interface.
最近的一项表面流变学研究表明，α-环糊精（αCD）与阴离子表面活性剂（S）的水溶液在液/气界面表现出显著的粘弹性，这在类似体系中尚未观察到。扩张模量比αCD+水和S+水的二元混合物大几个数量级。流变响应在定性上与物种的本体分布有关，2∶1包合物（αCD2∶S）起着基本作用。在这项工作中，我们开发了一个模型，该模型考虑了在液/气界面有序排列的2∶1包合物之间的偶极-偶极相互作用。当该模型应用于特定实验条件时，发现扩张模量和表面张力对浓度和温度的依赖性与数据非常吻合，清楚地表明偶极-偶极相互作用决定并控制了界面的流变行为。
