(722c) Electroacoustic Colloidal Assembly in a Continuous Flow-through Microfluidic Device

External fields are capable of directing the assembly of colloidal particles into ordered colloidal crystals with applications to electro-optical conversion of electromagnetic energy for existing (e.g., photovoltaics, reconfigurable antennae) and emerging technologies (e.g., optical computing, sub-diffraction limited imaging, meta-materials). Many external field approaches are based on batch-scale processing, which limits the throughput of colloidal crystals. Increasing throughput with convection leads to hydrodynamic shear stresses that can disrupt colloid crystal microstructure. In this talk, we report on a continuous flow-through approach to assembling colloidal crystals that relies on electroacoustic transport to drive crystallization. Colloidal dispersions are exposed to electroacoustic fields of different intensities to understand how acoustic pressure acts to compress colloidal ensembles. The ensemble density distribution within our device is compared to a model that accounts for the particle flux due to shear-induced diffusion and acoustophoresis. We track order parameters that assess the degree of hexagonal close-packing in order to understand the microstructural evolution as a function of acoustic pressure and flow rate conditions. We implement a force-biased Monte Carlo simulation to model the competition between acoustophoretic transport and shear-induced migration. The model is validated by comparing density and order parameter distributions.