Surface modification of polymers by atomic oxygen using ECR plasma

Polyimide (PI) and fluorinated ethylene propylene (FEP) samples were exposed to atomic oxygen ions of average energy ∼12 eV and flux ∼5 × 1013 ions cm−2 s−1, produced in an ECR plasma. The fluence of the oxygen ions was varied from sample to sample over a range from ∼5 × 1016 to 2 × 1017 ions cm−2. The pre- and the post-irradiated samples were characterized by the contact angle, AFM and XPS techniques. The results indicate that the surface roughness of the polyimide increased from ∼7 to ∼65 nm, that of the FEP from ∼5 to ∼28 nm and the surface regions of both polyimide and FEP changed from hydrophobic to hydrophilic after exposure to atomic oxygen ions. The XPS results reveal that the concentrations of carbon, fluorine and oxygen changed even at a fluence of ∼1017 ions cm−2 of the atomic oxygen ions. The results of the present study reveal that significant changes have been induced in the surface morphology and adhesion properties of polyimide and FEP after exposure to atomic oxygen ions.