Mapping the variation of the translocation<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi></mml:math>scaling exponent with nanopore width

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.