Effect of Plasma Treatment and Ion-Plating on Adhesion of Metallized Polyimide and Poly(ethylene terephthalate)

Abstract

The adhesion of thin metal films on polymeric substrates is a very important factor in any application of metallized plastics. The effect of plastic surface treatment by O₂ plasma and R.F. ion-plating on adhesion was investigated. Polyimide [PI] and poly(ethylene terephthalate) [PET] were used. The following results were obtained: 1) When the polymeric surface was pretreated with high power O₂ plasma (the radio frequency (R.F.) power: 100W), the peel strength at the Fe/PI interface abruptly increased with increase in the treatment time. When it was pretreated with lower power O₂ plasma (the R.F. power: 15W), its peel strength increased at earlier treatment time and then kept constant. ESCA spectra of the polymeric surface treated with O₂ plasma were analyzed, and the surface density of functional groups on the polymeric surface was determined. The production of the functional groups and their surface density were correlated with the adhesion of thin metal films on polymeric substrate. 2) When the ion-plating technique was used to metallize plastics, the peel strength at the polymer/metal interface increased with increase in the R.F. power and the accelerating voltage. The deposited metal formed chemical bonding with the polymeric substrate through oxygen atoms at the interface as shown by ESCA or FT-IR results.