title: Shape-tailored colloidal molecules obtained by self-assembly of model gold nanoparticles with flexible polyelectrolyte.
abstract: We study for the first time the structure of stable finite size clusters (i.e., colloidal molecules) obtained by self-assembly of cationic gold nanoparticles (i.e., atoms) mediated by a flexible polyanion. We reveal with nondenaturizing techniques a striking structural transition from 1D small chains of 12 gold nanoparticles (AuNPs) with a self-avoiding conformation to 3D fractal clusters of 130 AuNPs with short-range ordering around the charge inversion threshold. Interestingly, these well-defined structures are obtained by simple mixing in water without anisotropic functionalization or external forces. As a preliminary step, we introduce a new synthesis pathway leading to well-defined cationic AuNPs of controllable size that can be dispersed in H2O or D2O without aggregation and ligands' self-assemblies. On this occasion, we point for the first time that usual procedures do not enable to eliminate cationic ligands' self-assemblies that could play an undesired role in AuNPs' self-assembly through electrostatic interactions.
authors: †Laboratoire Matière et Systèmes Complexes, UMR CNRS 7057, Université Paris Diderot, 10 rue A. Domon, 75013 Paris, France.|‡Laboratoire Léon Brillouin, UMR 12 CEA-CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France.
authors: Li
authors: L
authors: Shi
authors: †Laboratoire Matière et Systèmes Complexes, UMR CNRS 7057, Université Paris Diderot, 10 rue A. Domon, 75013 Paris, France.|‡Laboratoire Léon Brillouin, UMR 12 CEA-CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France.
authors: Eric
authors: E
authors: Buhler
authors: ‡Laboratoire Léon Brillouin, UMR 12 CEA-CNRS, CEA Saclay, 91191 Gif-sur-Yvette, France.
authors: François
authors: F
authors: Boué
authors: †Laboratoire Matière et Systèmes Complexes, UMR CNRS 7057, Université Paris Diderot, 10 rue A. Domon, 75013 Paris, France.
authors: Florent
authors: F
authors: Carn