| The objective of Professor Walker’s
research 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.
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