Mapping the variation of the translocation $\ensuremath{\alpha}$ scaling exponent with nanopore width

Mapping the variation of the translocation $α$ scaling exponent with nanopore width

Hendrick W. de Haan and Gary W. Slater

Phys. Rev. E 81, 051802 – Published 14 May 2010

Abstract

The unbiased translocation of a coarse-grained polymer through a nanopore is investigated via Langevin dynamics simulations for polymers ranging from $N = 19$ to 299 monomers in length and pore widths $r_{p}$ ranging from 1 to 10 times the monomer diameter. The exponent $α$ derived from the scaling of the translocation time $τ$ with respect to the molecular weight $N$ is found to be heavily dependent on $r_{p}$ and increases from a value of 2.2 for $r_{p} = 1.0$ up to a saturation value of 3. The details of the translocation process also reveal that the average number of monomers in the pore $⟨ n_{p} ⟩$ not only varies as translocation proceeds but that for any polymer where the radius of gyration is greater than the radius of the available pore width, $⟨ n_{p} ⟩$ decreases with increasing $N$ . Using these data to rescale the results according to a blob picture, the results retain sensitivity on the pore geometry as $α$ varies from 2.2 to 2.65—a range which covers all results reported in previous studies.