(65c) Shape Memory-Enabled Microparticles for Tailoring the Flow Behavior and Aging of Suspensions

Particle suspensions are crucial in various natural and industrial processes, from maintaining healthy ecosystems and forming part of bodily fluids in living organisms to engineering daily-life products. Understanding the flow behavior of particle suspensions is an essential area of research with both fundamental and practical applications. The rheological properties of particle suspensions can be complex and may change with time, temperature, and imposed strain or shear rate. This complexity can make it challenging to predict and tailor the behavior of the suspension and design or optimize processes that consider these properties. Temperature-responsive polymers offer a way to engineer materials with reversible changes in their chemical and mechanical properties. However, most applications of temperature-responsive polymers focus on the tunability of bulk mechanical properties, with only a few examples of their use as polymeric particles to tune the flow behavior of suspensions. We designed stimuli-responsive particles to regulate the rheological properties of suspensions. We expand the use of temperature-responsive polymer materials to synthesize anisotropic, temperature-responsive particles with tunable shape and shape memory effects. We investigate the equilibrium and non-equilibrium properties and effect of temperature on the rheological properties of semidilute and dense suspensions. The stimuli-responsive particle suspensions' linear and non-linear shear rheology and time effects are studied using torsional rheometry to elucidate concentration-dependence variation and temperature effects. We show that shape memory and the strength of attractive interactions modify the flow behavior and promote tunable suspension aging and thixotropy. Using stimuli-responsive materials that change the single-particle physicochemical properties provides an alternative route to modify the flow behavior of suspensions.