Gold layers were prepared on poly(ethylene terephtalate) substrate by diode sputtering and vacuum evaporation. The mean layer thickness was determined by atomic absorption spectroscopy. Sheet electrical resistance and reflection of electromagnetic waves were used for the characterization of layers. Surface morphology of the layers was determined using atomic force and scanning electron microscopy. While the sputtering was found to proceed with two different rates, the vacuum evaporation proceeds at a constant rate. Rapid decrease of the sheet resistance was observed during sputtering, depending on the layer thickness, in contrast to vacuum evaporation. This can be due to different mechanisms of the Au deposition. According to the measured reflection of electromagnetic waves, the layers prepared by both techniques, i.e., sputtering and vacuum evaporation, are discontinuous for thicknesses below 4 nm, continuous but heterogeneous for thickness from 4 to 10 nm, and continuous and homogeneous for thickness above10 nm. The morphology of the layers prepared by vacuum evaporation does not depend on the layer thickness. Rounded clusters are observed on the surface of the evaporated layers. The layers prepared by sputtering exhibit significantly different morphology with much smaller, pointed clusters.
Polyethyleneterephtalate (PET) and polytetrafluorethylene (PTFE) foils were modified by plasma discharge. The effect of plasma modification on polymer surface wettability and on properties of gold coatings were studied as a function of time from plasma exposure (aging time) and polymer substrate temperature. Thickness, sheet resistance, and surface topology of gold layers were studied. Aging of the plasmaexposed samples is accompanied by increase in contact angle, which is explained by rearrangement of the polymer segments in the polymer surface monolayer, and a decrease in the concentration of polar groups. The aging also leads to a decline in surface roughness R a measured by atomic force microscopy (AFM). Under deposition conditions, comparable thicknesses of deposited Au layers were prepared on pristine PET and plasma-treated PET and PTFE samples. The thinnest Au layers were evaporated onto pristine PTFE. The sheet resistance decreases with increasing thickness of Au layer. Plasma treatment leads to an increase of PTFE surface roughness, which becomes even more pronounced after Au deposition. A higher roughness shows that the PET samples are deposited with the Au layer at temperatures above the glassy transition temperature T g .
This work deals with characterization of polypropylene (PP) exposed to plasma discharge and gold layers deposited on the plasma modified PP. PP foils were exposed to Ar plasma and subsequently metallized with sputtered Au layer. Chemical structure of the plasma modified PP was studied using X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering (RBS). Wettability of the plasma modified PP and its changes during sample aging were determined by goniometry. Surface morphology of PP and deposited Au layers was measured with atomic force microscopy (AFM). Continuity of Au layers was characterized by measuring their sheet resistance. With increasing exposure time in the plasma discharge the water contact angle decreases and the polymer surface becomes more hydrophilic. During the aging of the plasma treated samples the contact angle increases again. Plasma treatment leads to a decrease of the PP surface roughness and to generation of oxygen-containing polar groups on PP surface. During sample aging the concentration of the oxygen-containing groups decreases.
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