Size Selective Adsorption of Gold Nanoparticles by Electrostatic Assembly

In this study, we show that electrostatic interactions between charged substrates containing preattached nanoparticles and bidisperse nanoparticle colloids can be engineered to achieve size selective adsorption and dimer formation. Electrostatic interactions enable the assembly of the dimers with high yields due to the interplay between attractive and repulsive forces resulting from charges confined on the particles and substrate surfaces. We investigate in detail the effects of temperature, incubation time and particle mixing ratios of the bidisperse solution and benchmark the size-selectivity for different scenarios. Driving forces of the assembly process are explained using DLVO theory (Derjaguin, Landau, Verwey, and Overbeek).