Low temperature plasma has been used to modify the surface properties of polymers to a large extent. The effects of ECR microwave plasma with carbon dioxide (CO\-2) on the wettability of the poly(phthalazinone ether sulfone ketone) (PPESK) surface were discussed. Results showed that a shorter treatment time and a higher discharge power could give the best wettability of PPESK films. The toughness of the treated film surface increased with the discharge power. The wettability of PPESK films treated by CO\-2 plasma declined with the aging time after treatment, and the changing rate of different power is resemble. The increase in water contact angle for plasma treated PPESK surfaces upon ageing is mainly ascribed to the surface rearrangement of macromolecular segments, the loss of oxygen\|containing moieties introduced by the plasma treatment. ESCA analysis of CO\-2 plasma treated polymer surfaces showed that carbonyl groups could be increased by carbon oxide plasma treatment in short time.
