CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui Province, People's Republic of China.
J Chem Phys. 2011 Apr 7;134(13):135102. doi: 10.1063/1.3575239.
Using analytical techniques and Langevin dynamics simulations, we investigate the dynamics of polymer translocation into a narrow channel of width R embedded in two dimensions, driven by a force proportional to the number of monomers in the channel. Such a setup mimics typical experimental situations in nano/microfluidics. During the translocation process if the monomers in the channel can sufficiently quickly assume steady state motion, we observe the scaling τ ∼ N∕F of the translocation time τ with the driving force F per bead and the number N of monomers per chain. With smaller channel width R, steady state motion cannot be achieved, effecting a nonuniversal dependence of τ on N and F. From the simulations we also deduce the waiting time distributions under various conditions for the single segment passage through the channel entrance. For different chain lengths but the same driving force, the curves of the waiting time as a function of the translocation coordinate s feature a maximum located at identical s(max), while with increasing the driving force or the channel width the value of s(max) decreases.
利用分析技术和朗之万动力学模拟,我们研究了聚合物在二维环境中通过宽度为 R 的狭窄通道的动力学,驱动力与通道中单体的数量成正比。这种设置模拟了纳米/微流控中典型的实验情况。在易位过程中,如果通道中的单体能够足够快速地达到稳态运动,我们观察到易位时间 τ 与每个珠的驱动力 F 和每个链的单体数 N 的标度 τ ∼ N∕F。随着通道宽度 R 的减小,稳态运动无法实现,从而导致 τ 对 N 和 F 的非普遍依赖性。从模拟中,我们还推导出了在通道入口处通过单个片段的各种条件下的等待时间分布。对于不同的链长但相同的驱动力,通过通道入口的等待时间作为易位坐标 s 的函数的曲线具有位于相同 s(max) 的最大值,而随着驱动力或通道宽度的增加,s(max)的值减小。