**Polyelectrolyte Threading through a Nanopore**

PY Hsiao, POLYMERS, 8 (2016).

DOI: 10.3390/polym8030073

Threading charged polymers through a nanopore, driven by electric fields
E, is investigated by means of Langevin dynamics simulations. The mean
translocation time **GRAPHICS** is shown to follow a scaling law
**GRAPHICS** , and the exponent alpha increases monotonically from
**GRAPHICS** to **GRAPHICS** with E. The result is double-checked by the
calculation of mean square displacement of translocation coordinate,
which asserts a scaling behavior **GRAPHICS** (for t near tau) with beta
complying with the relation **GRAPHICS** . At a fixed chain length N,
**GRAPHICS** displayed a reciprocal scaling behavior **GRAPHICS** in the
weak and also in the strong fields, connected by a transition **GRAPHICS**
in the intermediate fields. The variations of the radius of gyration of
chain and the positions of chain end are monitored during a
translocation process; far-from-equilibrium behaviors are observed when
the driving field is strong. A strong field can strip off the condensed
ions on the chain when it passes the pore. The total charges of
condensed ions are hence decreased. The studies for the probability and
density distributions reveal that the monomers in the trans-region are
gathered near the wall and form a pancake-like density profile with a
hump cloud over it in the strong fields, due to fast translocation.

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