Translocation of a comb-like polymer out of a confined nanochannel driven by an external pulling force

Abstract We employ three-dimensional Langevin dynamics simulations to investigate the end-pulled translocation of a comb-like homopolymer through a nanopore, starting from a closed nanochannel. This investigation examines how factors such as confinement dimensions, nanopore sizes, polymer architecture, and the magnitude of the pulling force affect the mean translocation time, denoted as ⟨ τ ⟩ . We observe a linear decrease in the total free energy change, Δ F ( n ) , associated with confinement, which consistently remains negative. The simulation results of our study reveal that ⟨ τ ⟩ exhibits three distinct regimes and the non-monotonic variation with the aspect ratio δ , for fixed total chain size N and grafting density ρ . Similarly, the width of the nanochannel and nanopore size significantly influence the dynamics of translocation, such that ⟨ τ ⟩ exhibits two distinct regimes: the narrow and wide regimes for both the nanochannel and nanopore. For fixed N and side chain length N sc , while varying ρ , we find that, ⟨ τ ⟩ decreases monotonically with the grafting density. We also find a power-law between ⟨ τ ⟩ and the backbone length N bb as, ⟨ τ ⟩ ∼ N bb γ , where the scaling exponent γ = 0.86 ± 0.04 and γ = 0.86 ± 0.05 , for F  = 40 and F  = 50, respectively. Additionally, we establish the scaling relations of ⟨ τ ⟩ with N and N bb for fixed side chain number and length, under varying N bb . Thus, as the side chain length increases from N sc = 2 to N sc = 5 , we find the power-law dependence of ⟨ τ ⟩ with N as ⟨ τ ⟩ ∼ N α , where α shows a crossover from α = 2.58 ± 0.02 to α = 3.26 ± 0.15 . Similarly for varying ρ and N , we obtain a power-law dependence of ⟨ τ ⟩ on N bb as ⟨ τ ⟩ ∼ N bb γ , where γ shows a crossover from γ = 1.57 ± 0.09 to γ = 1.33 ± 0.06 . Moreover, the inverse proportionality of ⟨ τ ⟩ with the pulling force as ⟨ τ ⟩ ∼ F − 1 is another finding of this study. These results advance the fundamental understanding of polymer architecture on translocation dynamics, providing key insights for nanopore-based polymer transport applications.