Laura works on crystalline colloidal dispersions.
Colloidal dispersions display equilibrium fluid to crystal transitions with coexistence boundaries and nucleation rates comparable to predictions from statistical thermodynamics . Crystalline structures formed by these methods tend to be polycrystalline and lacking long range order. Additionally, formation of these structures require times ranging from several hours to several days. One way to accelerate crystal formation in metastable dispersions is to apply a field. When a field is applied to suspensions of repulsive hard spheres, the structures that form are determined by the balance among Brownian motion, hydrodynamic forces, and interparticle interactions. In these systems, microstructure rearranges to accommodate hydrodynamic and interparticle forces and conditions . Several field-induced methods have been developed to create colloidal crystals from charged spheres, however many of these methods of self-assembly are limited by time scales, particle size restrictions, and inability to control the properties of the 3-D structures formed. Examples of methods of field-induced assembly include sedimentation vertical deposition (dip coating) , magnetic , and electric field assisted assembly, and flow-assisted methods such as shear flow , and spin coating . To address the limitations of colloidal crystal formation we have studied spin coating as a potential method for large-scale production of high quality multilayer colloidal crystals. By imaging local structures formed by spin coating using, processing the images, and evaluation of local order parameters we have established a theory relating local order in spin coated structures to local stress and macroscopic strain . Further experiments include work in simple shear flow.