M. R. Chashmejahanbin - Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran.
Ali Salimi - Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran.
Amir Ershad Langroudi - Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran.

Plasma treatment is a suitable method for increasing wettability of a surface without changing in its bulk properties. Materials and methodsPP sheets (Polynar Co. Iran) were prepared by injectionmolding.1.9Specimens were treated by oxygen plasma (LF Plasma Diener Co. Deutschland) at a gas flow rate of50cm3/min at different times and powers. Contact angle measurements were obtained immediately afterplasma treatment (max 8 min.) by sessile drop method. The equation of Owens [1] was used to calculate the surface free energy, SFE of PP sheets.Non contact AFM, Dual scope/Raster scope C26, DME (Denmark) was used to capture the scan area of 5×5 μm2.