We carried out Brownian dynamics simulation studies of the translocation of single polymer chains across a nanosized pore under the driving of an applied field (chemical potential gradient).The translocation process can be either dominated by the entropic barrier resulteed from restricted motion of flexible polymer chains or by applied forces (or chemical gradient across the wall),we focused on the latter case in our studies.Caclulation of radius of gyrations at the two opoosite sides of the wall shows that the polymer chains are not in equilibrium during the translocation process.Despite this fact,our results show that the one-dimensional diffusion and the nucleation model provide an excellent description of the dependence of average translocation time on the chemical potential gradients,the polymer chain length and the solvent viscosity.In good agreement with experimental results and rtheoretical predictions,the translocation time distribution of our simple model shows strong non-Gaussian charactristics.It is observged that even for this simple tubelike pore geometry,more than one peak of translocation time distribution can be generated for proper pore diameter and applied field strengths.Both repulsive Weeks-Chandler-Anderson and attractive Lennard-Jones polymer-nanopore interaction were studied,attraction facilitates the translocation process by shortening the total translocation time distribution was found to decrease with increasing temperature,increasing field strength,and decreasing pore diameter.
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