Laboratory of Quantum and Computational Chemistry, Department of Physical Chemistry, Faculty of Chemistry, University of Sofia, 1 James Bourchier Avenue, 1164 Sofia, Bulgaria.
Langmuir. 2010 Jun 1;26(11):8081-92. doi: 10.1021/la904734b.
Extensive molecular dynamics simulations at room temperature were carried out for model films of two dissimilar lipids (DPPC and dicaprin) at the air/water interface. To study the peculiarities of the organization patterns at different average areas per molecule, surface concentrations corresponding to five almost equally spaced points along the isotherms of the two surfactants were considered. A variable of prime interest was the density distribution in a direction normal to the interface of the monolayer components: interfacial water and surfactant on one hand and the separate moieties of the lipids on the other hand. The packing pattern and cluster size dispersion were studied by means of Voronoi tessellation and radial distribution functions. Speculations regarding structural changes upon phase-state changes during film compression were made. Individual characteristics for surfactant heads and tails as well as for interfacial water were outlined and related to the available experimental data. An analysis of the diffusion coefficients revealed the limiting factors for lipid lateral and normal diffusion. Structural arguments in support of changes in monolayer dielectric properties with the area per molecule were provided.
在室温下，对两种不同脂质（DPPC 和二辛酸）的模型膜在空气/水界面进行了广泛的分子动力学模拟。为了研究不同平均分子面积下的组织模式的特点，考虑了对应于两种表面活性剂等温线上五个几乎等间隔点的表面浓度。一个主要关注的变量是单层成分（界面水和表面活性剂）与脂质单独部分之间垂直于界面的方向上的密度分布。通过 Voronoi 图和径向分布函数研究了堆积模式和簇大小分布。对膜压缩过程中相态变化时的结构变化进行了推测。概述了表面活性剂头和尾以及界面水的个体特征，并与可用的实验数据相关联。对扩散系数的分析揭示了脂质横向和法向扩散的限制因素。提供了支持单层介电特性随分子面积变化的结构论据。
