Egan Colin K, Hassanali Ali
The "Abdus Salam" International Centre for Theoretical Physics, I-34151 Trieste, Italy.
J Chem Phys. 2023 Sep 14;159(10). doi: 10.1063/5.0163849.
Recent vibrational sum frequency generation spectroscopic experiments [Sengupta et al., J. Phys. Chem. Lett. 13, 11391-11397 (2022)] demonstrated synergistic interfacial adsorption effects between the anionic dodecyl sulfate (DS-) and the polar, but charge-neutral hexaethylene glycol monododecyl ether (C12E6), surfactants. In this study, the interfacial adsorption thermodynamics underlying these synergistic effects are analyzed through free energy decompositions. A general decomposition method utilizing alchemical intermediate states is outlined. Combining free energy decompositions with the potential distribution theorem illuminates the statistical interpretations of correlated effects between different system components. This approach allows for the identification of the physical effects leading to synergistic adsorption thermodynamics of DS- binding to the air-C12E6-water interface. The binding properties are found to result from a combination of effects predominantly including energetic van der Waals stabilization between DS- and C12E6, as well as competing energetic and entropic effects due to changes in the interfacial water structure as a result of introducing a C12E6 monolayer into the bare air-water interface.
最近的振动和频产生光谱实验[Sengupta等人，《物理化学快报》13, 11391 - 11397 (2022)]证明了阴离子十二烷基硫酸盐(DS-)与极性但电荷中性的六甘醇单十二烷基醚(C12E6)表面活性剂之间的协同界面吸附效应。在本研究中，通过自由能分解分析了这些协同效应背后的界面吸附热力学。概述了一种利用炼金术中间态的通用分解方法。将自由能分解与势分布定理相结合，阐明了不同系统组分之间相关效应的统计解释。这种方法能够识别导致DS-与空气 - C12E6 - 水界面协同吸附热力学的物理效应。发现结合特性是由多种效应共同作用的结果，主要包括DS-与C12E6之间的范德华能稳定作用，以及由于在裸空气 - 水界面引入C12E6单分子层导致界面水结构变化而产生的能量和熵的竞争效应。
