Modeling the Electrokinetics of Nanoparticles for Controlled Assembly

We present a predictive framework for the controlled assembly of nanoparticles onto the surface of small (15 150 nm) electrode gaps using the dielectrophoretic (DEP) force. By combining Brownian dynamics (BD) simulations with continuum descriptions for the spatial distributions of nanoparticles, we arrive at a concise analytic description for the number of particles assembled as a function of the applied voltage, nanoparticle properties, and geometric parameters, such as the size of the electrode gap. Our model is predictive and successfully describes the presence of a voltage threshold, below which no assembly is observed.