Polymer Translocation out of Planar Confinements

Abstract

Polymer translocation in three dimensions out of planar confinements is studied in this paper. Three membranes are located at $z=-h$, $z=0$ and $z=h_1$. These membranes are impenetrable, except for the middle one at $z=0$, which has a narrow pore. A polymer with length $N$ is initially sandwiched between the membranes placed at $z=-h$ and $z=0$ and translocates through this pore. We consider strong confinement (small $h$), where the polymer is essentially reduced to a two-dimensional polymer, with a radius of gyration scaling as $R^{\tinytext{(2D)}}_g \sim N^{ν_{\tinytext{2D}}}$; here, $ν_{\tinytext{2D}}=0.75$ is the Flory exponent in two dimensions. The polymer performs Rouse dynamics. Based on theoretical analysis and high-precision simulation data, we show that in the unbiased case $h=h_1$, the dwell-time ${\tau }_d$ scales as $N^{2+ν_{\tinytext{2D}}}$, in perfect agreement with our previously published theoretical framework. For $h_1=\infty$, the situation is equivalent to field-driven translocation in two dimensions. We show that in this case ${\tau }_d$ scales as $N^{2ν_{\tinytext{2D}}}$, in agreement with several existing numerical results in the literature. This result violates the earlier reported lower bound $N^{1+\nu }$ for ${\tau }_d$ for field-driven translocation. We argue, based on energy conservation, that the actual lower bound for ${\tau }_d$ is $N^{2\nu }$ and not $N^{1+\nu }$. Polymer translocation in such theoretically motivated geometries thus resolves some of the most fundamental issues that are the subjects of much heated debate in recent times.

Minor changes; 18+ pages, 8 figures, 5 tables, to appear in J. Phys: Cond. Mat

References in corpus (1)

• Influence of polymer-pore interactions on translocation

Cited by in corpus (3)

• Dynamical Scaling Exponents for Polymer Translocation through a Nanopore
• Comment on ``Passage Times for Unbiased Polymer Translocation through a Narrow Pore''
• Pore-blockade Times for Field-Driven Polymer Translocation