Wettability of glow discharge polymers

Treatment of good adhering glow discharge polymerized propylene (GDPP) coatings with reactive gas plasma from oxygen, nitrogen, or water (produced in a tubular reactor operation at 27.1 MHz) results in surfaces characterized by more hydrophilic interactions. Zisman's plots indicate a change in surface energy after such treatment. Transmission electron microscopy depicts that the pronounced improvement in wettability of GDPP polymer after oxygen plasma treatment in part results from the high surface development in the polymer. However, the effect is not permanent. The wettability of plasma‐treated polymer diminishes with time and reaches a limiting value in 2–3 months indicating structural rearrangements at the polymer surface. Argon, carbon monoxide, or bromotrichloromethane plasma does not change the polymer surface wettability significantly. In contrast to the O 2 plasma‐treated GDPP polymer, a glow discharged polymer synthesized from ϵ‐caprolactam maintains its inherent hydrophilicily over an extended period of time.