Using an incremental mean first passage approach to explore the viscosity dependent dynamics of the unbiased translocation of a polymer through a nanopore.
Noting the limitations of the standard characterization of translocation dynamics, an incremental mean first passage process methodology is used to more completely map the unbiased translocation of a polymer through a nanopore. In this approach, the average time t(0) required to reach successively increasing displacements for the first time is recorded - a measure shown to be more commensurate with the mean first passage nature of translocation. Applying this methodology to the results of Langevin dynamics simulations performed in three dimensions across a range of viscosities, a rich set of dynamics spanning regular diffusion at low viscosities to sub-diffusion at higher viscosities is revealed. Further, while the scaling of the net translocation time τ with polymer length N is shown to be viscosity-dependent, common regimes are found across all viscosities: super-diffusive behaviour at short times, an N-independent backbone consistent with τ ∼ N(2.0) at low viscosities and τ ∼ N(2.2) at higher viscosities for intermediate times, and N-dependent deviations from the backbone near the completion of translocation.
Physics Department, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Hendrick W
HW
de Haan
Gary W
GW
Slater
D003198:Computer Simulation; D004058:Diffusion; D008956:Models, Chemical; D058608:Nanopores; D011108:Polymers / Q000737:chemistry*; D014783:Viscosity
D011108:Polymers