Effect of ligand shell structure on the interaction between monolayer-protected gold nanoparticles

Here we present a comparative analysis of two types of equally monodisperse gold nanoparticles (similar to 8 nm in diameter), one coated only with dodecanethiol ligands and the other coated with a mixture of dodecanethiol and 4-methylbenzenethiol ligands. The former particles ('homoligand') have a homogeneous coating, while the latter ones ('rippled') show a striated structure composed of phase-separated ribbon-like domains of alternating composition. A combined scanning tunneling and transmission electron microscopy study shows that homoligand nanoparticles interdigitate into one another less than rippled particles and readily form hexagonally packed supracrystals, while rippled particles are trapped in more disordered 'glassy' arrangements.