物理化学学报 >> 1994, Vol. 10 >> Issue (11): 998-1003.doi: 10.3866/PKU.WHXB19941107

研究论文 上一篇    下一篇

Langmuir膜分子动力学模拟中的头基效应

张红宇, 韦钰   

  1. 东南大学吴健雄实验室,南京 210028
  • 收稿日期:1993-09-24 修回日期:1994-03-23 发布日期:1994-11-15
  • 通讯作者: 张红宇

Head Group Effect on Molecular Dynamics Simulation of Labgmuir Monolayers

Zhang Hong-Yu, Wei Yu   

  1. Chien-Shiung Wu Laboratory of Southeast University,Nanjing 210028
  • Received:1993-09-24 Revised:1994-03-23 Published:1994-11-15
  • Contact: Zhang Hong-Yu

摘要:

运用分子动力学方法研究了Langmuir膜的结构和相变特性,比较了不同的头基模型对模拟的影响.发现在压膜过程中,膜分子的结构和排列存在相变,其中,分子脂肪链的倾角随着膜内每分子所占面积的增大而增大,分子链内无序的主要原因是脂肪链两端二面角的扭曲造成的.由不同模型模拟得出,带电模型的分子分布比较紊乱,倾角较小.这说明亚相环境和头基的不同,会影响模拟得的膜分子的排列,选择合理的头基模型非常重要.

关键词: 分子动力学, 相变, Langmuir膜, 头基

Abstract:

The structure and thermodynamics of stearate Lamgmuir film were studied using Molecular Dynamics and the effect of head group model on the simulation was also studied. The monolayer experienced two phase transitions during compression. The molecular chains tilted to their neighbors with a collective behavior and the bigger the density of the film is, the less tilted the chains are. The disorder occuring in molecules is mainly caused by the torsion of the dihedrals at the two ends of the molecular chains. It can be seen from the comparison of different models that the distribution of molecules with charged heads is more disordered and the tilted angle is a little bit smaller than those of neutral heads, which shows the difference in head group and subphase could influence the results of simulation, and it is important to find more reasonable head group model to improve the simulation.

Key words: Molecular Dynamics, Phase transition, Langmuir films, Head group