Chemically and physically patterned surfaces can be used as templates to guidenano- and micro- scale particle assembly, but the design is often limited by an inabilityto sufficiently characterize how pattern features influence local particle-surfaceinteractions on the order of thermal energy, kT. The research outlined in this dissertationdescribes comprehensive optical microscopy (i.e. evanescent wave, video)measurements and analyses of many-body and multi-dimensional interactions, dynamicsand structure in inhomogeneous colloidal fluid systems. In particular, I demonstratehow non-intrusive observation of an ensemble of particles diffusing past each other andover a physically patterned surface topography can be used to obtain sensitive images ofenergy landscape features. I also link diffusing colloidal probe dynamics to energylandscape features, which is important for understanding the temporal imaging processand self-assembly kinetics. A complementary effort in this dissertation investigated theuse of external AC electric fields to reversibly tune colloidal interactions to producemetastable ordered configurations. In addition, the electrical impedance spectra associated with colloidal assemblies formed between interfacial microelectrode gaps wasmeasured and consistently modelled using representative equivalent circuits.Significant results from this dissertation include the synergistic use of the verysame colloids as both imaging probes and building blocks in feedback controlled selfassemblyon patterns. Cycling the AC field frequencies was found to be an effectiveway to anneal equilibrium colloidal configurations. Quantitative predictions ofdominant transport mechanisms as a function of AC electric field amplitude andfrequency were able to consistently explain the steady-state colloidal microstructuresformed within electrode gaps observed using video microscopy. A functional electricalswitch using gold nanoparticles was realized by reversibly forming and breakingcolloidal wires between electrode gaps. Extension of the concepts developed in thisdissertation suggest a general strategy to engineer the assembly of colloidal particles intoordered materials and controllable devices that provide the basis for numerousemerging technologies (e.g. photonic crystals, nanowires, reconfigurable antennas,biomimetic materials).
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