J. Zekonyte

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 (10 12 –10 16 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. 2003 Elsevier Science B.V. All rights reserved.

Mechanisms of argon ion-beam surface modification of polystyrene

Abstract The surface characteristics of polymers are important factors determining their interfacial properties and their technological performance. Changes in physical and chemical properties of a polymer film may be induced by subjecting the material to a variety of surface modification techniques, one of which is ion-beam modification. In order to understand the underlying mechanisms X-ray photoelectron spectroscopy (XPS) was used to study the alterations of the polystyrene (PS) surface after Ar-ion treatment under well controlled conditions with low ion doses from 10 12 to 10 16 cm −2 . The ion bombardment leads to surface functionalization, loss of aromaticity, and free radical formation. Induced surface cross-linking and the formation of polar groups raised the surface glass transition temperature of PS film.

Etching rate and structural modification of polymer films during low energy ion irradiation

Various polymers were sputtered with low energy Ar+ ions of 1 keV in order to determine their etching rate. Hydrocarbons, oxygenated, fluorinated and nitrogen-containing glassy polymers with a broad range of the glass transition temperature (Tg) were chosen. The etching rate was measured using a profilometer, and X-ray photoelectron spectroscopy. At the same time the surface chemical modification, and the surface glass transition temperature were studied. Comparing the sputter rate to the various polymer properties a correlation among the Tg, cross-link density, and sputter rate was found. In addition, the sputter rate as a function of the integral ion fluence proved to exhibit a sharp increase in the initial regime of very low fluence. The results are discussed in terms of the characteristics of the polymers

Effects of thermal annealing of thin Au film on Fe40Ni38Mo4B18

Abstract Thin films (∼20 nm) of Au were vapour-deposited at room temperature on melt-spun amorphous ribbon specimens of the alloy Fe 40 Ni 38 Mo 4 B 18 . The specimens were subsequently annealed at 823 and 873 K in a flowing nitrogen atmosphere and in low vacuum conditions (∼10 −1 –10 −3 mbar) in order to observe any dispersion of Au in the alloy matrix. The depth profiles of Au from annealed specimens were obtained by XPS and showed depth distribution of Au up to several hundred nanometres in the alloy in sharp contrast to those obtained from specimens annealed in ultra-high vacuum. An analysis of the XPS peaks of the alloy constituents suggests strong surface segregation of the matrix elements and the growth of an oxide film on the surface during thermal annealing. It is suggested that the driving force for Au dispersion in the alloy is provided by the reactivity of matrix elements with oxygen present in the annealing media.

Adsorption of Noble Metal Atoms on Polymers

Metallized polymers are nowadays of considerable technological importance and are widely used in industry ranging from food packing to optical data storage. A detailed understanding of the metal/polymer interface properties plays a key role in most applications of metallized polymers. During the last few years, much work has been performed to study the different aspects of metal/polymer interface formation using various microscopic and surface-sensitive techniques. For recent and detailed reviews on metal/polymer interfaces, we refer the reader to refs. 1 and 2 and the article by F. Faupel et al. in the present proceedings. In this article we only consider the metal adsorption phenomena during metal/polymer interface formation by thermal evaporation of a noble metal onto a polymer.