Nanoparticles have been self‐assembled using a novel technique described as nanoxerography (see cover). A method has been developed by the authors to pattern charge with 100 nm resolution. These charge patterns act as “receptors” for nanoparticles (see Figure), enabling the directed self‐assembly of nanoparticles from a powder, gas phase (aerosol), and liquid phase (suspension).

This paper reports on the directed self-assembly of nanoparticles onto charged surface areas with a resolution of 200 nm from the liquid phase and 100 nm from the gas phase. The charged areas required for this type of nanoxerographic printing were fabricated using a parallel method that employs a flexible, electrically conductive, electrode to charge a thin-film electret. As electrodes, we used metal-coated polymeric stamps and 10 µm thick doped silicon wafers carrying a pattern in topography. Each electrode was brought in contact with a thin-film electret on an n-doped silicon substrate. The charge pattern was transferred into the thin-film electret by applying a voltage pulse between the conductive electrode and the silicon substrate. Areas as large as 1 cm 2 were patterned with charge with 100 nm scale resolution in 10 s. These charge patterns attract nanoparticles. A liquid-phase assembly process where electrostatic forces compete with disordering forces due to ultrasonication has been developed to assemble nanoparticles onto charged based receptors in 10 s from a liquid suspension. A gas-phase assembly process was developed that uses a transparent particle assembly module to direct particles towards the charged surface while monitoring the total charge of assembled particles. Nanoparticles were generated using a tube furnace by evaporation and condensation at the outlet. The electrostatically directed assembly of 10-100 nm sized metal (gold, silver) and 30 nm sized carbon particles was accomplished with a resolution 500-1000 times greater than the resolution of existing xerographic printers.