Interfaces in solutions of randomly charged rods

We study the interfacial properties of systems containing like-charged rods with charge fluctuations along their length. We show that it is possible to describe clusters of rods in terms of the sum of a bulk free energy and a surface free energy. It is not obvious that this is valid for electrostatic systems, since the interactions are long-ranged, and the effective interactions between rods are not pairwise-additive.