Zeng Lili, Reisner Walter W
Department of Physics, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.
Phys Rev E. 2022 Jun;105(6-1):064501. doi: 10.1103/PhysRevE.105.064501.
We use molecular dynamics simulation to probe the nonequilibrium physics of single nanochannel-confined semiflexible polymers in a homogeneous flow field. The flow field compresses the polymer against the end of the nanochannel, simulating an experiment of a nanochannel confined chain compressed against a slit barrier. The flow-based compression gives rise to a packing of the chain against the channel end that possesses a striking organization, consisting of interweaving of folds and circular coils. For stiff chains at low flow, we find that the organization is dominated by repeated hairpin folds. For stiff chains at higher flow, we observe that circular coils arise along with the folds, with folding and coiling domains becoming interwoven at the highest flow speeds. Chain organization is retained even when the chain persistence length is on order of the channel width. We show that the global polymer organization, consisting of a number of defined folds and coiled loops, arises from the minimization of the total chain free energy.
我们使用分子动力学模拟来探究单根纳米通道受限的半柔性聚合物在均匀流场中的非平衡物理。流场将聚合物压向纳米通道的末端，模拟了纳米通道受限链被压向狭缝屏障的实验。基于流的压缩导致链在通道末端堆积，这种堆积具有惊人的结构，由褶皱和圆形线圈的交织组成。对于低流速下的刚性链，我们发现这种结构主要由重复的发夹状褶皱主导。对于高流速下的刚性链，我们观察到圆形线圈与褶皱一起出现，在最高流速下，折叠和盘绕区域相互交织。即使链的持久长度与通道宽度相当，链的结构也能保留。我们表明，由许多确定的褶皱和盘绕环组成的全局聚合物结构源于总链自由能的最小化。
