Synthese und elektronenmikroskopische Untersuchung kontrolliert gewachsener, ligandstabilisierter Goldkolloide sowie theoretische Überlegungen zur Oberflächenbelegung durch Kolloide / Synthesis and Electron Microscopic Investigation of Controlled Grown, Ligand Stabilized Gold Colloids and Theoretical Considerations on the Covering of Surfaces by Colloids

Abstract

18 nm Gold colloids are used as seeds for a controlled growth of 36 nm colloids which are then stabilized by P(m-C 6 H 4 SO 3 Na) 3 . These colloids can be isolated as golden leaflets and are readily soluble in water in virtually any concentration. Electron microscopic investigations prove a very small particle size distribution. X-ray powder diffraction and molecular weight determinations support the results of the electron microscopic investigations. The distance between the colloidal particles in two-dimensional layers corresponds to double-layers of phosphane ligands around each colloid, twice 1.2 nm. Isolated colloids seem to possess thicker ligand shells. A single 44 nm colloid shows a corona of about 7.2 nm thickness, corresponding to 12 phosphane layers. A quantitative description of two-dimensional packing densities is suggested using a novel theoretical model. By means of Monte Carlo simulations the two-dimensional structures are formed during the covering of supports of different geometry can be calculated.