Transport of a comb-like polymer across a nanochannel subject to a pulling force

We investigate the dynamics of comb-like polymer translocation through a nanochannel using three-dimensional Langevin dynamics simulations based on a coarse-grained chain model. A comprehensive set of simulations are performed to examine the effects of system parameters such as the grafting density<i>ρ</i>of the side chains, the polymer chain length, the nanochannel dimensions, and the magnitude of the pulling force on the translocation dynamics. For a given polymer chain length, keeping the backbone length is constant while varying<i>ρ</i>, we have found that the dependence of the mean translocation time⟨τ⟩on<i>ρ</i>is non-monotonic, with a maximum translocation time for a specific<i>ρ</i>at which the translocation is the slowest. The simulation results also show that⟨τ⟩is not significantly affected by the channel width above a certain radius, while the comb-like polymer translocation is hindered by a narrower channel due to increased interactions between the chain monomers and the channel. In addition,⟨τ⟩increases linearly with the nanochannel length. A linear scaling relationship between the mean translocation time⟨τ⟩and the chain length<i>N</i>of polymer is obtained,⟨τ⟩∼N. Similarly, the dependence of⟨τ⟩on the backbone chain sizeNbbhas a quasi-linear dependence,⟨τ⟩∼Nbb. On the other hand, the translocation velocity<i>v</i>follows a power-law relationship with the polymer chain length<i>N</i>asv∼N-1. The mean translocation time also shows an inverse linear relationship with the magnitude of the pulling force<i>F</i>,⟨τ⟩∼F-1. The power-law relationships discovered in this study contribute to the fundamental understanding of the comb polymer translocation dynamics and to establishing a framework for further investigations in this field.