Condensation coefficients of noble metals on polymers: a novel method of determination by x-ray photoelectron spectroscopy

We developed a method to determine condensation coefficients, C, of noble metals on polymer surfaces and to determine cluster sizes by means of XPS only, or in combination with transmission electron microscopy (TEM), The surface concentration of the adatoms was determined using a mathematical correction of the XPS intensity that takes into account cluster growth of the noble metals on the polymer surfaces. We establish our method with experimental results of C for Cu and Ag on pyromellitic dianhydride (PMDA)-4,4'-oxydianiline (ODA) polyimide, bisphenol-a polycarbonate, trimethylcyclohexane bisphenol-A polycarbonate, polystyrene and Teflon AF 1601, Values of C for Ag determined with the XPS method agree well with those of radiotracer measurements. The condensation coefficient varies by three orders of magnitude from 1 to 0.002, depending on the deposition parameters and properties of the adsorbents. The method can be applied in general to investigate the deposition of non-wetting metals on solid surfaces. Copyright (C) 2000 John Wiley & Sons, Ltd.