Soft materials, in particular so-called complex fluids, contain microstructures ranging in length from 1 to 1000 nanometers. These polyatomic structures typically determine the physical properties of the system in question and often exhibit forms of self-organization. Currently we are focusing on the development of multiple light scattering probes for investigating complex fluid structure and dynamics. We augment these multiple light scattering studies with static and dynamic light scattering, small angle neutron and x-ray scattering, mechanical rheometry, and various spectroscopic probes. Our ultimate goal is to establish relationships between microscopic structure/dynamics, processing conditions, and macroscopic properties.

      We are particularly interested in applying colloidal and macromolecular science to problems of biotechnological interest. Supramolecular complexes for drug and gene delivery attract most of our attention at this time. Our studies include DNA complexation with polymers and/or surfactants, the delivery of therapeutic agents to cells, liposome-liposome and liposome-cell interactions, and emulsion/liposome production processes. In addition to scattering and spectroscopic probes of these phenomena, we use a novel cross flow field flow fractionation-static light scattering hybrid instrument to overcome the impact of size polydispersity on these investigations.

      The properties of macromolecules near interfaces are much different than those within the bulk material. These polymer interfaces occur in many technologies and quite often determine the overall performance of the device or process under consideration. Rapid, noninvasive, inexpensive spectroscopic interface probes are of particular interest. The research team synthesizes, characterizes, and utilizes optical fiber-based fluorescence and infrared sensors in polymer composite processing applications. Our goals are: (1) to establish the connection between any measurable signals and polymer composite physical properties with an eye towards process control applications and (2) to determine the potential of these techniques for investigating fundamental polymer interface physics.