Cosurfactant and cosolvent effects on surfactant self-assembly in supercritical carbon dioxide
Cosurfactant and cosolvent effects on surfactant self-assembly in supercritical carbon dioxide
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DOI：
10.1063/1.1855291
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发表时间：
2005-03-01
影响因子：
4.4
通讯作者：
Gubbins, KE
中科院分区：
文献类型：
--
作者：
Chennamsetty, N;Bock, H;Gubbins, KE
采用格子蒙特卡罗模拟方法研究了醇类添加剂对超临界二氧化碳中表面活性剂自组装的影响。我们观察到，所有研究（模型）醇降低临界胶束浓度。醇的烃链越长，醇浓度越高，还原越强。发现短链醇集中在聚集体的表面活性剂层中，取代表面活性剂分子并导致聚集体数目的强烈减少和聚集体数目的大量增加。另一方面，在聚集体中仅发现少量具有较长链长的醇分子，导致聚集数略有增加。然而，在相同的聚集数的聚集体的结构性质，如尺寸和密度分布的影响不显着。因此，短链醇作为助表面活性剂，直接影响聚集体的性质，而具有较长烃链的醇作为助溶剂，改变溶剂的性质。然而，两个极端之间的过渡是渐进的。(C)2005年美国物理学会。
The impact of alcohol additives on the self-assembly of surfactants in supercritical carbon dioxide is investigated using lattice Monte Carlo simulations. We observe that all studied (model) alcohols reduce the critical micelle concentration. The reduction is stronger the longer the hydrocarbon chain of the alcohol, and the higher the alcohol concentration. Short-chain alcohols are found to concentrate in the surfactant layer of the aggregates, replacing surfactant molecules and leading to a strong decrease of the aggregation number and a large increase of the number of aggregates. On the other hand, only a small number of alcohol molecules with longer chain length are found in the aggregates, leading to a slight increase in the aggregation number. However, structural properties such as size and density profiles of aggregates at the same aggregation number are not influenced markedly. Consequently, short-chain alcohols act as cosurfactants, directly influencing the properties of the aggregates, while alcohols with longer hydrocarbon chains work as cosolvents, altering the properties of the solvent. However, the transition between both extremes is gradual. (C) 2005 American Institute of Physics.