Decoding the Rheology of Biopolymer Solutions and Complex Coacervates

Biopolymers offer a sustainable alternative to fossil-derived materials, combining renewability and biodegradability with structural and functional diversity. Their complex architectures, however, complicate dissolution, processing, and prediction of structure-property relationships. This work uses rheology as a central tool to probe how molecular features and interactions shape viscoelastic behavior. Ionic liquids are explored as versatile solvents that both dissolve rigid biopolymers and tune their network structures, while polyelectrolyte complexation provides a complementary strategy to form dynamic, reversible assemblies. Across cellulose, agar, guar gum, chitosan, and hyaluronic acid systems, rheological and scaling analyses reveal how molecular weight, chain rigidity, solvent quality, and electrostatics govern elasticity, relaxation, and flow. Together, these studies establish design principles for tailoring gelation, processability, and adhesive performance. By integrating insights from solvent effects, associative interactions, and polymer architecture, this work advances understanding of biopolymer rheology and supports the rational design of sustainable, high-performance soft materials.