Emerging nanoscale devices built upon nanoparticle arrays (e.g. photonic materials, nanoporous membranes and biosensors) will most likely require solution-phase directed self-assembly of colloidal and nanoparticles. In order to ensure proper operation in such devices, a high level of direction and control are required. This work is aimed at employing external fields (electrical and/or shear) to create an appropriate driving force on the particles to assemble large colloidal arrays. This directed process needs high selectivity and precision to be useful.

Of specific interest in my work is the development of highly ordered particle arrays by either dielectrophoretic assembly (AC electric field) or large amplitude oscillatory shear (LAOS). In order to understand the fundamentals and dynamics of the construction of the colloidal crystals, properties are measured by rheology, SANS, DLS, SLS and electrophoretic mobility. These results will be combined with Stokesian Dynamics simulations to confirm the fundamental physics driving externally directed self-assembly.