Modulation of structure, morphology and wettability of polytetrafluoroethylene surface by low energy ion beam irradiation

Polytetrafluoroethylene (PTFE) films were irradiated under vacuum with 3 keV Argon ions (Ar+) and fluences ranging from 0.5 × 1018 to 2 × 1018 ions/cm2. Ion induced PTFE surface modifications of structural, morphological and wettability nature were studied by means of Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, atomic force microscopy and force spectroscopy, and contact angle measurements. FTIR analysis indicated defluorination of PTFE due to the rupture of C–C and C–F bonds. The values of droplet contact angle of the irradiated samples decreased gradually with the increasing ion flux, and were found to be very sensitive to the environmental humidity under which the measurements were made. The experimental results show that the surface chemical bond, morphology, and wettability of irradiated PTFE samples depend closely on the argon ion flux.