Polymer-melt-based manufacturing processes for nanostructures offer high-rate, environmentally friendly, and commercially viable alternatives to solution-based methods. In this work, electrophoresis of a model carbon black and polystyrene system with moderate viscosity was used to investigate the viability of adapting nanoassembly processes to the high viscosity environment of polymer melts. The presence of polystyrene did not prevent deposition of carbon black, but deposition rates decreased at shorter deposition times; deposition was not linear With increasing applied voltage; and greater solution concentrations reduced the critical voltages (i.e., the voltage at which the rate of deposition changed). X-ray photoelectron spectroscopy (XPS) results and comparison of experimental data with Hamaker's model showed that about 1.6% of the available polystyrene was initially deposited with the carbon black. At voltages above the critical voltage, the deposited mass was less than the Hamaker prediction, indicating the formation of electrically insulating layers on the electrodes. The overall behavior suggests that polymer melt-based processes could be employed for high-rate fabrication of nano-optical devices, biochemical sensors, and nanoelectronics.