Electrostatic Directed Assembly of Colloidal Microparticles Assisted by Convective Flow

Electrostatic directed assembly of colloidal particles on charged patterns, that is, nanoxerography, has proven to find innovative applications in plasmonics, anticounterfeiting, or particle sorting. However, this technique was restricted to dispersions of nanoparticles whose diameters are typically below 100 nm. The combination of experiments and simulations shows that this limitation is due to an uncontrolled dewetting of the substrate and to the low mobility of large particles. The "convective nano-xerography" process developed in this work overcomes this limit and allows making selective and dense assemblies of micrometer sized particles expanding by a factor 40 the size range foreseeable.