论文标题
自由悬浮的近晶膜中的岛屿结合
Coalescence of Islands in Freely-Suspended Smectic Films
论文作者
论文摘要
在空气中自由悬浮的几个分子层的近晶液晶膜被用作模型系统，以研究二维中流体的合并。高速视频显微镜用于观察膜的岛屿的聚合，在膜的圆盘形区域，这是由与沿岛边界的边缘位错相关的线张力驱动的过程，并受到液晶液晶和周围空气中粘性耗散的限制。连接合并岛的桥梁的早期生长揭示了动态的速度要比Hopper的经典流体动力学模型慢于真空中的两个无限长，流体圆柱体的结合模型，这是由于在后台膜中和空气中未包括在霍珀理论中的空气中的差异所致。在后期，椭圆形合并的岛屿以指数形式放松至圆形，以最初为Langmuir膜中流体域的演化而定量地描述的速率。
Smectic liquid crystal films a few molecular layers thick that are freely suspended in air are used as a model system to study the coalescence of fluids in two dimensions. High-speed video microscopy is used to observe the coalescence of islands, which are thicker, disk-shaped regions of the film, in a process driven by the line tension associated with edge dislocations along the island boundaries and limited by viscous dissipation in the liquid crystal and in the surrounding air. The early time growth of the bridge connecting the merging islands reveals much slower dynamics than predicted by Hopper's classical hydrodynamic model of coalescence of two infinitely long, fluid cylinders in vacuum, a discrepancy proposed to be due to significant dissipation in the background film and in the air that is not included in Hopper's theory. At late times, the elliptical merged island relaxes exponentially to a circular shape, at rates that are described quantitatively by a model originally developed for the evolution of fluid domains in Langmuir films.
