Polymer-mediated assembly of gold nanoclusters

Low molecular weight, less than or equal to 4000, polymers containing amine functionalities such as polyethyleneimine or poly-L-lysine serve as a scaf fold for assembly of carboxylic acid functionalized gold clusters. The asse mbly produces at the liquid-air interface of the reaction medium, free-stan ding, space-filling films that are one monolayer thick. Assembly was promot ed through the formation of peptide bonds by the addition of a carbodiimide but also proceeds in the absence of the carbodiimide by ion palling. The m orphology of the films is sensitive to the nature of the acid coating on th e gold clusters with mercaptododecanoic acid and mercaptosuccinic acid form ing more regular films than those coated with thioctic acid.