(607f) Multi-Spatiotemporal Investigation of the Structure-Property Relationship of Polysaccharide-Based Hydrogels

Consumer product attributes are often conflicting, such that molecular engineering can be necessary to yield a successful commercial product. A common example of conflicting attributes is the need for shelf and transportation stability in products comprised of suspensions of emulsions and/or colloids along with good portability, high shear stability, and dispensability. Nanostructured fluids where physical interactions provide both this desired yield-stress feature as well as strong shear-thinning behavior are required, and are often comprised of self-assembled wormlike micelles, clay gels, or microgels. Critically, after the mixing or flowing of the materials, the thixotropic properties of the fluids allow subsequent recovery of the structure either in the product container or during scale-up and packaging processing. Design such systems requires understanding of the desired structural architecture, the history of the applied strain, and flow-induced structural alteration in these fluids. Here we explore the mechanisms by which tailored suspensions of mixed polymer gums create self-healing and yield-stress structured fluids.

Static and dynamic light scattering, microrheology such as diffusive wave spectroscopy (DWS), and mechanical rheology with simultaneous small-angle neutron scattering (SANS) quantified both static and dynamic structural characteristics, which provide important insights into molecular engineering process in multi-spatiotemporal scales. Sprayable yield-stress polysaccharide-based nanostructured fluids with a variety of concentrations (xanthan-konjac-based mixture) are investigated both in the presence and the absence of added KCl. Semi-quantitative connections are made between molecular architecture and the desired applicable properties, providing new insights valuable for successful design of advanced materials.