Physical theory of ionomer aggregation in water

This article presents a physical theory for the aggregation of ionomer molecules in aqueous solution. To study this phenomenon, we consider a system of charged rigid rods with uniform surface charge immersed in water. The free-energy functional derived for this system consists of hydrophobic and direct electrostatic contributions as well as entropic terms. Energy minimization gives the stable aggregation number as a function of surface charge density, surface tension, geometric parameters, and density of rods in solution. We provide configuration diagrams of the system, which display the impact of the hydrophobic and electrostatic interaction strengths on the stabilization of finite-size bundles.