Loison C, Mareschal M, Schmid F
Max Planck Institut für Chemische Physik fester Stoffe, Nöthnitzer str. 40, D-01187 Dresden, Germany.
J Chem Phys. 2004 Jul 22;121(4):1890-900. doi: 10.1063/1.1752884.
We investigate pores in fluid membranes by molecular dynamics simulations of an amphiphile-solvent mixture, using a molecular coarse-grained model. The amphiphilic membranes self-assemble into a lamellar stack of amphiphilic bilayers separated by solvent layers. We focus on the particular case of tensionless membranes, in which pores spontaneously appear because of thermal fluctuations. Their spatial distribution is similar to that of a random set of repulsive hard disks. The size and shape distribution of individual pores can be described satisfactorily by a simple mesoscopic model, which accounts only for a pore independent core energy and a line tension penalty at the pore edges. In particular, the pores are not circular: their shapes are fractal and have the same characteristics as those of two-dimensional ring polymers. Finally, we study the size-fluctuation dynamics of the pores, and compare the time evolution of their contour length to a random walk in a linear potential.
我们使用分子粗粒化模型，通过对两亲物 - 溶剂混合物进行分子动力学模拟来研究流体膜中的孔。两亲性膜自组装成由溶剂层分隔的两亲性双层的层状堆叠。我们关注无张力膜的特殊情况，在这种情况下，由于热涨落，孔会自发出现。它们的空间分布类似于一组随机的排斥性硬磁盘的分布。单个孔的尺寸和形状分布可以通过一个简单的介观模型得到令人满意的描述，该模型仅考虑与孔无关的核心能量以及孔边缘处的线张力惩罚。特别地，孔不是圆形的：它们的形状是分形的，并且具有与二维环形聚合物相同的特征。最后，我们研究了孔的尺寸涨落动力学，并将其轮廓长度的时间演化与线性势中的随机游走进行了比较。
