Fluorocarbon thin-film deposition on polymer surfaces from low-energy polyatomic ion beams

Low energy polyatomic ion deposition is attractive for selective surface modification of advanced materials. Surface modification by fluorocarbon (FC) thin film deposition is widely used for many technological applications. Thus, polymer surface modification by FC thin film deposition was carried out using mass-separated low energy FC ion beams. X-ray photoelectron spectroscopy, atomic force microscopy and air/water contact angles were employed to examine how the FC film chemistry, morphology, and long term stability depend on incident ion structure, kinetic energy, and fluence. Molecular dynamics simulations were performed to support experimental data.; 25–100 eV CF₃+ and C₃F ₅+ ion deposition on polystyrene (PS) surface was examined. CF₃+ and C₃F₅+ each formed a distribution of different FC functional groups on PS in amounts dependent upon the incident ion energy, structure, and fluence. Both ions deposited mostly intact upon the surface at 25 eV. The total fluorine and fluorinated carbon content were increased with ion energy. The fluorination efficiency was higher for the larger ion. The simulations revealed that the fragmentation behavior depends on the incident ion structure and its energy. The simulations also confirmed that FC ions only penetrated a few angstroms into the surface.; The compositional changes of 25–100 eV CF₃+ and C₃F₅+ ion-modified PS surfaces were examined after being exposed to atmosphere for four and eight weeks. The FC films oxidized in atmospheric conditions. Oxygen incorporation into the ion-modified surfaces increased with ion energy due to higher surface bond breakage and active site formation at high collision energy. Overall, the aging process of these ion-deposited films appeared similar to that of plasma-deposited films.; Mass-selected 50 eV C₃F₅+ ion deposition was employed to create chemical gradient thin films on polymethylmethacrylate (PMMA) by variation of the ion fluence across the substrate surface. The surface chemistry changed continuously from native polymer to FC film while wettability decreased linearly across the gradient surface. The data verified creation of a chemical and wettability gradient on PMMA by 50 eV C₃F ₅+ ion-deposition. The production of FC films on polystyrene, silicon, and aluminum surfaces implied that low energy polyatomic ion-deposition is a general method for production of chemical gradients on various substrates.; 10 and 45 eV CF₃+ ions were employed to functionalize carbon nanotubes. The combination of experiments and simulations demonstrated that low-energy ion deposition is a feasible method for functionalization, cross-link formation, and connection of carbon nanotubes.