Influence of jet-to-substrate distance on plasma etching of polyamide 6 films with atmospheric pressure plasma

In this study, polyamide 6 films were treated with different jet-to-substrate distances to investigate how it influenced the etching effect of plasma treatment. When the samples were too close or too far from the nozzle, the etching rate was almost not measurable. When the distance was 2 mm, the etching rate was larger than that of other distance. Decrease in contact angle was observed under 2 mm or 3 mm of jet-to-substrate distance. However, the contact angle had no change when jet-to-substrate distance was 1 mm or 6 mm. It can be seen that the peel strength increased when jet-to-substrate distance was 2 mm or 3 mm, and the peel strength was the largest when jet-to-substrate distance was 2 mm. However, the peel strength had no change when jet-to-substrate distance was 1 mm or 6 mm. These results were corresponding to SEM and XPS results.