A molecular dynamics study of monolayers of nonionic poly(ethylene oxide) based surfactants
A molecular dynamics study of monolayers of nonionic poly(ethylene oxide) based surfactants
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DOI：
10.1021/la0354640
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发表时间：
2004-02-17
期刊：
影响因子：
3.9
通讯作者：
Drummond, CJ
中科院分区：
文献类型：
--
作者：
La Rosa, M;Uhlherr, A;Drummond, CJ
报道了非离子聚环氧乙烷表面活性剂单分子膜的分子动力学模拟。具体而言，醇乙氧基化物和烷基酚乙氧基化物的不同的分子结构的结构-行为关系的发展方面进行了比较。界面密度分布用于评估单分子膜的结构，水和油渗透到单分子膜中，以及水溶性和疏水性的溶剂化。链构象描述符用于检查表面活性剂的分子结构。模拟结果表明，单层的醇乙氧基化物是相当多的扩散比他们的烷基酚对应物，与包装的大小所决定的的脂肪。除支化醇乙氧基化物外，醇乙氧基化物单层内体相的混合随着亲水长度的增加而增加。相比之下，烷基酚聚氧乙烯醚在单层内的堆积由分子中的芳核控制。邻近分子的芳环之间没有观察到特定的相互作用。烷基酚聚氧乙烯醚的单层比它们的醇对应物更致密，导致本体水相和油相的更有效分离。
Molecular dynamics simulations of monolayers of nonionic, poly(ethylene oxide) based surfactants are reported. Specifically, alcohol ethoxylates and alkylphenol ethoxylates are compared in terms of the varying architecture of the molecules for the development of a structure-behavior relationship. Interfacial density profiles are used to assess the structure of the monolayers, the penetration of water and oil into the monolayers, and the solvation of the hydrophiles and hydrophobes. Chain conformational descriptors are used to examine the molecular structure of the surfactants. The simulations revealed that monolayers of alcohol ethoxylates are considerably more diffuse than their alkylphenol counterparts, with the packing being governed by the size of the hydrophile. With the exception of the branched alcohol ethoxylate, the intermixing of the bulk phases within monolayers of alcohol ethoxylates increases with increasing hydrophile length. By comparison, the packing of alkylphenol ethoxylates within the monolayer is governed by the aromatic nucleus in the molecule. No specific interaction is observed between the aromatic rings of neighboring molecules. Monolayers of alkylphenol ethoxylates are more compact than their alcohol counterparts, resulting in more effective separation of the bulk water and oil phases.