Molecular dynamics simulation of amphiphilic molecules in solution: micelle formation and dynamic coexistence.
Molecular dynamics simulation of amphiphilic molecules in solution: micelle formation and dynamic coexistence.
复制标题
DOI：
10.1063/1.3105341
复制
发表时间：
2009-04
期刊：
影响因子：
--
通讯作者：
Susumu Fujiwara;T. Itoh;M. Hashimoto;R. Horiuchi
中科院分区：
文献类型：
--
作者：
Susumu Fujiwara;T. Itoh;M. Hashimoto;R. Horiuchi
采用分子动力学方法研究了具有显式溶剂分子的两亲性粗粒刚性分子的胶束形成和动态共存过程。我们的模拟表明，通过在较高温度下猝灭溶液中两亲分子的随机构型，在较低温度下观察到三种孤立的胶束（圆盘状、圆柱形和球形胶束）。胶束的形状随着亲水相互作用的增加由圆盘变为圆柱，再变为球形，但对疏水相互作用的变化不太敏感。这一事实表明，亲水相互作用起着重要的作用，在确定胶束形状的相互作用参数的范围内使用。在一定的相互作用参数范围内，两种胶束形态动态共存。通过对动态共存过程的详细分析，确定了圆柱形胶束和球形胶束的动态共存过程伴随着胶束的聚结和破碎，而圆盘形胶束和圆柱形胶束的动态共存过程则不伴随胶束的聚结和破碎，而是呈现出胶束之间的连续变化。
The micelle formation and the dynamic coexistence in amphiphilic solution are investigated by molecular dynamics simulation of coarse-grained rigid amphiphilic molecules with explicit solvent molecules. Our simulations show that three kinds of isolated micelles (disk, cylindrical, and spherical micelles) are observed at a lower temperature by quenching from a random configuration of amphiphilic molecules in solution at a higher temperature. The micellar shape changes from a disk into a cylinder, and then into a sphere as the hydrophilic interaction increases whereas it is not so sensitive to the variation of the hydrophobic interaction. This fact indicates that the hydrophilic interaction plays an important role in determining the micellar shape in the range of the interaction parameters used. It is also found that in a certain interaction parameter range, two kinds of micellar shapes coexist dynamically. From the detailed analyses of the dynamic coexistence, it is ascertained that the dynamic coexistence of a cylindrical micelle and a spherical micelle accompanies the coalescence and fragmentation of micelles while that of a disk micelle and a cylindrical micelle does not, but exhibits the continuous change between them.