Surface-restructuring behavior of aged PTFE irradiated by a high-flux nitrogen ion beam

Polytetrafluoroethylene (PTFE) was irradiated by a high-flux nitrogen ion beam. The influence of experimental parameters was investigated by varying ion beam energy from 2 to 20 keV with the same flux of 1.4×1017 ions/cm2. XPS, SEM, AFM, and wettability were employed to study structures and properties of the treated PTFE samples. All of the as-irradiated samples were aged in air for 1 year. After aging, five chemical bonds, CF3, CF2, CF, CO, and carbon bonds were observed on the surfaces of the aged samples. The intensities of various chemical bonds changed with increasing ion beam energy. The surface-restructuring behavior was observed on the surfaces of the aged samples irradiated by ion beam with energies of 2 and 5 keV. The surface roughness and water droplet contact angle of the aged PTFE samples irradiated with 2 and 5 keV ion beams improved obviously, and those of the aged PTFE samples irradiated with 10 and 20 keV ion beams kept basically no change. The experimental results suggest that the ion beam energy strongly affected the surface chemical bond, microstructure, and wettability of the aged PTFE samples.