Computational Prediction of Adsorption Equilibrium for Nonionic Surfactants at the Oil/Water Interface
Computational Prediction of Adsorption Equilibrium for Nonionic Surfactants at the Oil/Water Interface
复制标题
非离子表面活性剂在油/水界面吸附平衡的计算预测
DOI：
10.1021/acs.langmuir.9b02193
复制
发表时间：
2019
期刊：
影响因子：
3.9
通讯作者：
Toshiyuki Osakai
中科院分区：
文献类型：
--
作者：
Naoki Somekawa;Atsuki Yamauchi;Kazuo Eda;Toshiyuki Osakai
应用非Bornian溶剂化模型预测了非离子表面活性剂在油（O）/水（W）界面上的吸附平衡。在非Bornian模型中，忽略了长程静电相互作用的微小贡献，并基于短程溶质分子（或离子）-溶剂相互作用-空穴形成、库仑、极化、电荷转移等来制定溶剂化或分解能。这些相互作用能由分子表面上的局部电场（Ei）的零阶、一阶和二阶函数给出，其可以通过密度泛函理论计算来估计。在本研究中，我们认为吸附过程是一个分子在O/W界面的“部分”转移。采用非Bornian的非离子分子转移吉布斯自由能半经验方程，成功地预测了烷基醇（1-十二醇、1-辛醇和1-己醇）在1，2-二氯乙烷/W界面上的吸附态.在吸附态下，可以估算出醇的取向角（θ）、旋转角（ω）和渗透到O相中的深度（d）。此外，还可以从理论上估算O和W的吸附能（ΔGad°，O→ I和ΔGad°，W→I）。所研究的醇的ΔGad°，O→ I值与用滴重法测得的值符合得很好。
The non-Bornian solvation model has been applied for predicting the adsorption equilibrium for nonionic surfactants at the oil (O)/water (W) interface. In the non-Bornian model, the small contribution from the long-range electrostatic interaction is ignored, and the solvation or resolvation energy is formulated based on the short-range solute molecule (or ion)–solvent interactions—cavity formation, Coulomb, polarization, charge transfer, etc. These interaction energies are given by zero, first, and second-order functions of the local electric field (Ei) on the molecular surface, which can be estimated by density functional theory calculation. In the present study, we considered an adsorption process as “partial” transfer of a molecule across the O/W interface. Using a non-Bornian, semi-empirical equation for the Gibbs energy of transfer of nonionic molecules, the adsorption states of alkyl alcohols (1-dodecanol, 1-octanol, and 1-hexanol) at the 1,2-dichloroethane/W interface were successfully predicted. The orientation angle (θ), the rotation angle (ω), and the penetration depth into the O phase (d) of the alcohols in the adsorption state could be estimated. Furthermore, the energies for the adsorption from O and W (ΔGad°,O→Iand ΔGad°,W→I) could be estimated theoretically. The values of ΔGad°,O→Ifor the alcohols studied were in good agreement with those determined experimentally by the drop-weight method.