Controlling size of gold clusters in polyaniline from top–down and from bottom–up

Polyaniline forms a strong complex with chloroaurate at the protonated imine sites. Here we report on an electrochemical procedure that allows preparation of gold clusters by adding gold atoms one-by-one (“bottom–up” approach). It is contrasted with the “top–down” approach in which the growth of multi-atom Au clusters was also controlled electrochemically. Our results confirm that both the amount and the size of gold clusters affect the properties of the composite material.