The Interplay of Polymer Structure and Solvent Ordering on The Thermodynamics of Polyelectrolyte Solutions

From adhesives to pharmaceuticals, complex coacervation appears in many industrial applications and consumer products, motivating growing interest in the underlying thermodynamics and morphology. However, a significant challenge remains in building a reliable theoretical formulation that captures long-range electrostatic correlations and properly relates nanoscale structure and fluctuations to collective thermodynamic behavior. We study the effect of dipole ordering on the electrostatic potential near a charged surface and the phase behavior of oppositely charged polymer solutions. Our theoretical model of a solution of polyelectrolytes within a polar solvent aims to accurately capture polymer structure and solvent ordering at the nanoscale. We leverage exact results for the statistical behavior of the wormlike chain model in tandem with the random phase approximation. We show that the choice of chain structure factors predicts a wide range of phase behavior over a range of polymer lengths when accounting for quadratic order fluctuation corrections. We also demonstrate that our explicit treatment of the polar solvent leads to more significant charge-charge interactions near the polymers.