  The efficiency of nanopore-based biosequencing techniques requires fast
anionic polymer capture by like-charged pores followed by a prolonged
translocation process. We show that this condition can be achieved by setting a
pressure-solvation trap. Polyvalent cation addition to the KCl solution
triggers the like-charge polymer-pore attraction. The attraction speeds-up the
pressure-driven polymer capture but also traps the molecule at the pore exit,
reducing the polymer capture time and extending the polymer escape time by
several orders of magnitude. By direct comparison with translocation
experiments [D. P. Hoogerheide et al., ACS Nano 8, 7384 (2014)], we
characterize as well the electrohydrodynamics of polymers transport in
pressure-voltage traps. We derive scaling laws that can accurately reproduce
the pressure dependence of the experimentally measured polymer translocation
velocity and time. We also find that during polymer capture, the electrostatic
barrier on the translocating molecule slows down the liquid flow. This
prediction identifies the streaming current measurement as a potential way to
probe electrostatic polymer-pore interactions.
