Controlled growth of nano-size metal clusters on polymers by using VPD method

A completely dry technique (VPD) for the preparation of a metal cluster onto a polymer surface or between two polymer layers opens up very good possibilities to control the two dimensional dispersion of the metal clusters and their size during variation of the deposition parameters or the polymer surface treatment. The kinetics of heterogenous nucleation and the growth of nano-size metal clusters (Ni, Ag, Cu, Au) on polymers with different chemical composition (PMDA-ODA polyimide, polystyrene and Teflon AF) are studied by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). In contrast to preferred nucleation and significantly. incomplete condensation on the surface of Teflon AF and PS random nucleation and well defined cluster distribution was observed on PMDA-ODA polyimide. It was shown that cluster size and cluster distribution can be influenced in a wide range (some order of magnitude) by the variation of the preparation parameters. Ar ion beam treatment of polymers with low ion dose (10¹²-10¹⁶ cm^-2) as well as predeposition of a trace amount of a reactive metal can be successfully used to prepare a definite cluster structure due to creation of adsorption sites on polymer surface.