(306f) Designing Material Dynamics in Polyelectrolyte Complexes

Polyelectrolyte complexes (PECs) are formed through the electrostatic interaction of oppositely charged polymers. Depending on the solution conditions and choice of polymers, polyelectrolyte complexation can result in the formation of both solid precipitates and/or a liquid-liquid phase separation known as complex coacervation. We have recently used linear viscoelasticity to explore the nature of this liquid-to-solid transition for the model system of poly(4-styrenesulfonic acid, sodium salt) (PSS) and poly(diallyldimethyl ammonium chloride) (PDADMAC) in the presence of potassium bromide (KBr). The use of time-salt superposition facilitated the unambiguous characterization of this transition as a salt-driven physical gelation. Here, we extend these efforts, performing a systematic investigation into the effect of polymer chemistry and molecular weight on the resulting material dynamics. The goal of this work is to establish a molecular-level understanding of the dynamic mechanical response of polyelectrolyte complex materials to facilitate their use across a wide range of applications.