Nonlinear Rheological Behavior of Dynamic Covalent Gels

Hydrogels with dynamic linkers have garnered intense interest for applications that require flow, including injectable delivery vehicles and 3D bioprinting inks. However, to fully enable these applications, there remains a need to understand how linking chemistry affects gelation and nonlinear rheological properties. To probe this relationship, we developed synthetic multi-arm polyethylene glycol (PEG) gels linked with dynamic covalent bonds.

• Dynamic covalent hydrogels exhibit non-monotonic flow curves under steady shear, with shear thickening behavior that depends on exchange kinetics of linkers.
• Transient shear measurements indicate chain stretching is responsible for shear thickening.
• These results will guide hydrogel design for injectable gels and 3D bioprinting inks.
• This work supports the IRG goals of developing strategies for dynamic polymeric depletants and materials with rheo-adaptive behavior.