Modification of polymer surfaces by far-ultraviolet radiation of low and high (laser) intensities

Far-ultraviolet radiation (e.g. 185 nm from a mercury resonance lamp or 193 nm from a pulsed excimer laser) is highly effective in modifying the surfaces of a variety of polymers because of its short penetration depth (< 3000 A ̊) and its high (>0.1) quantum yield for bond breaking. With continuous low-level irradiation at 185 nm in the presence of specific gases functional groups can be introduced on the surface while etching is kept at a low rate. In contrast, the pulsed laser radiation at 193 nm causes ablative photodecomposition leading to a surface showing negligible reaction with the surrounding atmosphere. This process can be conveniently used in controlled etching of polymers.