Rheology of Microstructurally Rearranged Polyelectrolyte Complex Hydrogels

In this poster, we present rheological data related to the swelling and dehydration response of polyelectrolyte complex (PEC) hydrogels. PEC hydrogels are self-assembled from ABA + CBC triblock polyelectrolytes (PEs) due to electrostatic attraction and increased entropy from counterion and water molecule release. These hydrogels experience a myriad of microstructures that are influenced by both internal (charged-block length, PE concentration) and external (salt, pH) parameters. In this study, we establish PEC hydrogels as equilibrium structures through a series of controlled swelling and dehydration-rehydration experiments by probing the microstructural rearrangements with small-angle scattering experiments. Furthermore, we investigate the effect of these rearrangements on the shear properties of the PEC hydrogels by performing rheology measurements. We present our findings on the moduli of PEC hydrogels that were diluted to lower PE concentrations and the moduli of PEC hydrogels that were de- and then rehydrated to various PE concentrations by comparing them to the moduli of their pristine counterparts at the same PE concentrations. Additionally, we present our results on the moduli of mixtures of PEC hydrogels with initially distinct microstructures. We show that PEC microstructure and the resulting rheological properties can be modulated through dilution, dehydration, and mixing of PEC hydrogels demonstrating in situ tunability.