Superhydrophilic polymer surface modification by low energy reactive ion beam irradiation using a closed electron Hall drift ion source

A gridless closed electron Hall drift plasma accelerator with very low energy (< 200 eV) and high current density (∼ 1 mA/cm2) was adopted for polymer surface modification. Ar, N2, O2, and N2O gases were used for the generation of plasma and the ions were irradiated on polyimide and polyvinylidene fluoride with the ion fluence of 5 × 1015/cm2–1 × 1018/cm2. By the irradiation of O2+ at the very low ion fluence of 5 × 1015/cm2 corresponding to 1 s treatment time, the wetting angle of PI and PVDF were greatly reduced from 78° and 61° to less than 2° and N2O+ ion irradiation showed analogous results. The attainment of superhydrophilic polymer surface can be explained by the formation of hydrophilic group induced by low energy reactive ion beam irradiation. From the results, it is revealed that the very low energy ion beam irradiation can be used as an effective and productive ion source compared with conventional gridded ion source for the enhancement of surface energy of polymer.