Allen Erik C, Rutledge Gregory C
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Chem Phys. 2009 May 28;130(20):204903. doi: 10.1063/1.3139025.
Density dependent, implicit solvent (DDIS) potentials, the generation of which has been described previously [E. C. Allen and G. C. Rutledge, J. Chem. Phys. 128, 154115 (2008); E. C. Allen and G. C. Rutledge, J. Chem. Phys. 130, 034904 (2009)], are used in this work to examine the self-assembly of a model surfactant system. While the measurement of thermodynamic properties in simulations of solvated micelles requires large computational resources or specialized free energy calculations, the high degree of coarse-graining enabled by the DDIS algorithm allows for the measurement of critical micelle concentration and aggregation number distribution using single processor NVT simulations. In order to evaluate the transferability of potentials derived from the DDIS methodology, the potentials are derived from simulations of simple monomeric solutes and used in the surfactant system without modification. Despite the high degree of coarse graining and the simplicity of the fitting simulations, we demonstrate that the coarse-grained DDIS potentials generated by this method reliably reproduce key properties of the underlying surfactant system: the critical micelle concentration, and the average aggregation number. The success of the DDIS algorithm suggests its utility for more realistic surfactant models.
密度依赖型隐式溶剂（DDIS）势的生成方法已在之前有所描述[E. C. 艾伦和G. C. 拉特利奇，《化学物理杂志》128, 154115 (2008); E. C. 艾伦和G. C. 拉特利奇，《化学物理杂志》130, 034904 (2009)]，在本研究中用于考察一种模型表面活性剂体系的自组装。虽然在溶剂化胶束模拟中测量热力学性质需要大量计算资源或专门的自由能计算，但DDIS算法实现的高度粗粒化使得能够使用单处理器NVT模拟来测量临界胶束浓度和聚集数分布。为了评估源自DDIS方法的势的可转移性，这些势从简单单体溶质的模拟中导出，并直接用于表面活性剂体系。尽管粗粒化程度很高且拟合模拟很简单，但我们证明通过该方法生成的粗粒化DDIS势能够可靠地再现基础表面活性剂体系的关键性质：临界胶束浓度和平均聚集数。DDIS算法的成功表明其在更实际的表面活性剂模型中的实用性。
