Surface Properties of Thin Gold Layers Sputtered on Polymers

Thin gold layers were sputtered on the foils of polypropylene-PP, polyethyleneterephthalate-PET, polystyrene-PS, polyethylene-PE and polytetrafluoroethylene-PTFE modified by Ar⁺ plasma. Surface properties of pristine, plasma treated and gold coated polymers were characterized by two-points method (sheet electrical resistance), electrokinetical analysis (zeta-potential, surface chemistry), goniometry (contact angle), electron paramagnetic resonance (concentration of radicals), atomic force microscopy (AFM, surface morphology and roughness) and scratch test (mechanical properties). Zeta potential and contact angle, as assumed, differ dramatically for plasma treated polymers and for the polymers deposited by Au layers. AFM images indicate that after gold deposition on polymers the surface roughness and the surface morphology change depending on pristine polymer surfaces (roughness and morphology) and sputtering time. Electrical measurements resulted in fact that with increasing layer thickness, the sheet resistance of the gold layer decreases for all polymers with increasing sputtering time. Lower adhesive destruction is observed on the gold layer deposited on plasma treated PE in comparison with pristine.