(334h) Revealing the Flow Properties of Polysaccharide-Based Nanostructured Fluids By Microfluidics
Novel microfluidic flow channels with pressure measurements comprised of shear, sudden contraction and hyperbolic contraction are created to enable probing both shear and extensional rheology relevant for designing advanced materials of interest. Simultaneous microscopy enables flow velocimetry, and rheology with small angle neutron scattering (SANS) quantifies the flow-induced structural alteration, which provides important insights into molecular engineering process. Polysaccharide-based nanostructured fluids (xanthan-konjac-based mixture) and polyethylene oxide solution are investigated. Stress created by deformed structure and molecules determines the flow behavior especially for extensional flow (through the contraction). Generalized Newtonian model, viscoelastic model, and thixotropic structure kinetic models are used to reveal the flow properties of the fluids. Semi-quantitative connections are made between molecular architecture and the transient and steady shear and extensional properties, providing new insights valuable for successful design of advanced materials.