Molecular dynamics simulations of sodium dodecyl sulfate micelle in water: The behavior of water
Molecular dynamics simulations of sodium dodecyl sulfate micelle in water: The behavior of water
复制标题
十二烷基硫酸钠胶束在水中的分子动力学模拟：水的行为
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发表时间：
2002
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影响因子：
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通讯作者：
M. Forbes
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文献类型：
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作者：
C. Bruce;S. Senapati;M. Berkowitz;L. Perera;M. Forbes
用5 ns显式原子分子动力学方法模拟了含7579个TIP3P水分子的60单体十二烷基硫酸钠胶束体系，考察了水在不同静电环境中的行为。对该体系的结构评价表明，水分子对胶束的渗透仅限于头基区，留下了一个12A的无水碳氢化合物核心。由于头基氧−水氢键的形成，头基附近的水分子表现出水−水氢键网络的扭曲。这种失真的动力学含义表现在偶极自相关函数、Φ(T)和平移扩散系数的衰减上。我们观察到，当胶束的第一溶剂化壳层中水分子的平移扩散系数减小不到其在主体水中的值的一半时，重定向关联函数的慢分量减慢了一个或两个数量级。
Using a 5 ns explicit atom molecular dynamics simulation of a 60 monomer sodium dodecyl sulfate micellar system containing 7579 TIP3P water molecules, the behavior of water in different electrostatic environments was examined. Structural evaluation of the system revealed that penetration of water molecules into the micelle was restricted to the headgroup region, leaving a 12 A water-free hydrocarbon core. Water molecules near the headgroup exhibit a distortion of the water−water hydrogen bonding network due to headgroup oxygen−water hydrogen bond formation. The dynamic implications of this distortion are manifested in the decay of the dipole autocorrelation function, Φ(t) and translational diffusion coefficient. We observe that while the translational diffusion coefficient of water molecules in the first solvation shell of the micelle is reduced by less than a half of its value in bulk water, the slow component of the reorientational correlation function is slowed by one or two orders of magnitude.