Translocation of Polymer Chains Through a Channel with Complex Geometries

The elastic behavior of a single chain transporting through complex channel which can be seen as the combination of three different channels (left channel, middle channel, and right channel, respectively) is investigated using the new pruned-enriched Rosenbluth method with importance sampling. The elastic force during the translocation process is calculated. At the entrance into the middle channel, there is the first plateau in the curve of the elastic force f(f>0) versus x, here x represents the position of the first monomer along the x-axis direction. When the first monomer moves to a certain position, a second plateau is observedwith the elastic force f<0, which represents spontaneous translocation. The free energy difference between the subchain in the right channel and the subchain in the left channel may drive the translocation. The influence of chain length and width of the left and right channels on the translocation process are also investigated. From the simulation results, more detailed explanations for the reason why the componenttranslocation time is not the same for different channels can be presented.