Polymer-mediated assembly of gold nanoclusters

Low molecular weight, ≤4000, polymers containing amine functionalities such as polyethyleneimine or poly-L-lysine serve as a scaffold for assembly of carboxylic acid functionalized gold clusters. The assembly produces at the liquid-air interface of the reaction medium, free-standing, space-filling films that are one monolayer thick. Assembly was promoted through the formation of peptide bonds by the addition of a carbodiimide but also proceeds in the absence of the carbodiimide by ion pairing. The morphology of the films is sensitive to the nature of the acid coating on the gold clusters with mercaptododecanoic acid and mercaptosuccinic acid forming more regular films than those coated with thioctic acid.