摘要
采用密度泛函理论中的B3LYP方法,在6-31+G(d)水平上对阴-非离子型表面活性剂正辛醇聚氧乙烯醚羧酸盐进行了几何构型优化,并考察了其与不同阳离子(Na+,Ca2+)之间的相互作用。量化计算结果表明:1)该表面活性剂的阴离子基团与阳离子结合时稳定构型均为2∶1型,即极性头中两个氧原子与阳离子发生稳定结合,并且非离子基团与Na+离子的结合能远小于阴离子基团与Na+离子的结合能;2)阳离子对表面活性剂电荷分布的影响主要集中在极性头中的原子、与极性头相连的α-亚甲基以及乙氧基中距离极性头最近的氧原子上;3)在静电相互作用下,表面活性剂在胶束中交错排列,形成稳定的镶嵌结构,且电荷分布在阳离子影响下保持动态平衡,在宏观上表现出耐盐性能。
The structure of Octanol polyoxyethylene ether carboxylate (C8 E3 C ) surfactant was optimized by density functional theory (DFT) at the B3LYP/6-13+G(d) level. Together the interaction between surfactant and cations were also studied. The results shows that:1 ) 2 : 1 type pair between the anionic group of surfactant and Na^+/ Ca^2+ was formed, in which two oxygen atoms of the polar group bounded with one cation;the binding energy between the nonionic group and Na^+ is much small than that between the anionic group and Na^+. 2) The effect of cations on the distribution of charges of surfactants mostly concentrated on three parts, i. e. atoms in polar group, a-methylene group connected with polar group and the oxygen atom attached to the ct carbon. 3 ) The surfactants in micelles staggered to form a stable mosaic structure driven by the electrostatic interaction. And the charge distribution maintains dynamic equilibrium under the influence of cations, which lead to excellent salt tolerance at the macro level.
出处
《齐鲁工业大学学报》
CAS
2015年第1期1-6,共6页
Journal of Qilu University of Technology
基金
国家自然科学基金项目(21173128)
关键词
阴-非离子表面活性剂
脂肪醇聚氧乙烯醚羧酸盐
密度泛函理论
anionic-nonionic surfactant
fatty alcohol polyoxyethylene ether carboxylate
density functional theory