  We characterize the role of charge correlations in the adsorption of a short,
rod-like anionic polyelectrolyte onto a similarly charged membrane. Our theory
reveals two different mechanisms driving the like-charge
polyelectrolyte-membrane complexation: in weakly charged membranes, repulsive
polyelectrolyte-membrane interactions lead to the interfacial depletion and a
parallel orientation of the polyelectrolyte with respect to the membrane; while
in the intermediate membrane charge regime, the interfacial counterion excess
gives rise to an attractive "salt-induced" image force. This furthermore
results in an orientational transition from a parallel to a perpendicular
configuration and a subsequent short-ranged like-charge adsorption of the
polyelectrolyte to the substrate. A further increase of the membrane charge
engenders a charge inversion, originating from surface-induced ionic
correlations, that act as a separate mechanism capable of triggering the
like-charge polyelectrolyte-membrane complexation over an extended distance
interval from the membrane surface. The emerging picture of this complexation
phenomenon identifies the interfacial "salt-induced" image forces as a powerful
control mechanism in polyelectrolyte-membrane complexation.
