(144f) Counter-Ion Mediated Polyelectrolyte Interactions: Simulation and Theory | AIChE

(144f) Counter-Ion Mediated Polyelectrolyte Interactions: Simulation and Theory


Van Tassel, P. - Presenter, Yale University
Antila, H., Aalto University
Sammalkorpi, M., Aalto University

Polyelectrolyte interactions govern many natural and technological processes. Recent experiments and simulations suggest like-charged polymers to attract one another under certain conditions, owing to preferential counter-ion positioning between the two chains. Such attraction may have significant implications to nucleic acid delivery and polyelectrolyte film formation. We address here the problem of like-charged polymer attraction using a coarse grained model, consisting of two similarly charged aligned cylinders, oppositely charged spherical counter-ions, and spherical salt species. Employing Monte Carlo simulation, we show polymer-polymer attraction to correlate strongly with a Coulomb coupling parameter, defined as the ratio of i) the electrostatic interaction energy of two counter-ions at the cylinder surface and ii) the thermal energy. A simple statistical mechanical model is proposed, where ions “condensed” to the cylinder surface are treated as a highly correlated 2-D one-component plasma, and ions away from the surface are treated in a mean field description. We discuss these results in light of recent experimental findings of significantly enhanced polyelectrolyte adsorption to electrified interfaces.