甜菜碱
化学物理
化学
羧酸盐
分子动力学
理论(学习稳定性)
化学工程
静电学
烷基
材料科学
计算化学
有机化学
物理化学
计算机科学
机器学习
工程类
作者
Fengfeng Gao,Guokui Liu,Shiling Yuan
标识
DOI:10.1016/j.apsusc.2017.02.087
摘要
Zwitterionic betaines are widely used as foam boosters due to these can enhance the stability of foam films. In this paper, mechanistic insights of betaine to improve the stability of alkyl-polyoxyethylene carboxylate (AEC) foam are provided by molecular simulation. In the simulation, we observe the electropositive nitrogen atoms in betaine interact with the electronegative sulfur atoms, an electrostatic structure is formed at the air/water interface. Interaction energies of the mixed surfactants are calculated by the quantum chemistry methods. The calculations show betaine-AEC and betaine–betaine possess attractive interaction, and that AEC–AEC has repulsion to each other. In the other words, the repulsion between the headgroups of anionic surfactants is relaxed by betaine. Additionally, the influence of concentration of betaine on the stability of foam films is also simulated. The RDF and coordination numbers show that the electrostatic structures become denser with the increasing concentration of betaine. Therefore, entry barrier is enhanced accordingly. The SMD simulation also demonstrates the same variation tendency of entry barrier. The simulation details provide vital supplements to experiments.
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