Phase Composition and Viscoelasticity of Non-Ideal Polyelectrolyte Complexes

Polyelectrolyte (PE) complexation is driven by electrostatic interactions between oppositely charged macromolecules in solution. The extent of complexation and properties of the complexes are influenced by a combination of the solution conditions under which complexation occurs (pH, ionic strength) and properties of the charged PEs (degree of ionization, molecular weight, chemistry). Experimental studies investigating phase behavior and rheology of polyelectrolyte complexes (PECs) have been performed with ideal systems, with well-controlled properties. However, in fields where PEs are utilized (biological systems, water treatment), the solution conditions and PE properties are non-ideal.  Previously, we noted that the phase composition of divalent salt-PEC systems stood in stark contrast to oft-studied monovalent salt-PECs. This manifested as a non-monotonic evolution in shear moduli with increasing divalent ion concentration. In this poster, we discuss the effects of non-idealities in PEs on the phase compositions of the PECs. Additionally, changes in PE properties will be shown to influence the shear response of PECs. Finally, the effect of ionic strength, in combination with non-idealities in PEs will be shown to influence the physical and shear properties of the PECs.