The objective of the group is to develop a fundamental understanding of the flow-induced microstructures which exist in complex fluids through a combination of macroscopic rheological measurements and in situ microstructural probes.
The need for a fundamental understanding of the flow-microstructure coupling is vital in the processing of complex polymeric systems and the formulation of multicomponent systems. For intelligent design and application of these types of materials, the coupling between flow and microstructure must be quantified.
Two phase systems which include macromolecules, i.e., immiscible polymer blends and emulsions, are rheologically complex. We are using optical techniques to probe the dynamic microstructure in these materials in both simple and complex flow fields. Of key interest is understanding how viscoelasticity, in any of the materials, influences structural changes and rheology.
The rheological behavior of systems containing multiple components, of which at least one is macromolecular, is a complicated yet relevant problem. Many of these systems exhibit flow-induced structures and rich non-equilibrium phase behavior. We are using small-angle neutron scattering to probe the flow-induced structures in micellar systems that contain linear aggregates and in systems with polymer-surfactant assemblies.