Colloids are often thought of as particulates in suspensions.  Using directed assembly, our group manipulates micron-sized particles using external forces fields, such as magnetic fields.  We link these particles together with DNA to form a colloidal “bead-spring-bead” system that can be used to describe polymer systems.  The particles can also form 2-D colloidal crystals when placed in a high frequency magnetic field.

We also study polymer and other multiphase flow systems in microfluidic systems.  Microfluidic systems provide unique opportunities to understand and analyze fluids using confined geometries. For example, aggregates of electrostatically stabilized polymers form gels that are not observed in bulk systems.  These aggregates can also be formed into new structures in microfluidic channels.

One class of foams can be described as a dispersion of bubbles in an aqueous solution.  These foams can be stabilized using surfactants, polymers, or particles.  Using microfluidic systems, we create mimics of porous media and visualize whether these foams are stabilized in the presence of oil for enhanced oil recovery applications.

Supported lipid membranes form a useful mimic for cell membranes.  We are interested in measuring changes in the surface free energies of these membranes when exposed to membrane proteins, lipases, and surfactants using microcantilevers.  Differences between free-standing and supported membranes have led to unique biophysical observations.

We are also developing novel silicon-based structures for lithium-ion batteries. By structuring silicon with pores, we are able to accommodate the swelling in the material as it undergoes lithiation.