Influence of source gas flow ratio on the proteins adsorbability of F-DLC film

The fluorinated diamond-like carbon (F-DLC) films are prepared by reactive magnetron sputtering under different gas flow radios with trifluoromethane (CHF3 ) and argon (Ar) used as source gases and pure graphite as a target on the surface of 316L stainless steel (SU316L). Factors which influence the protein adsorbability are discussed by double-stilled water, BCA and FTIR spectra. The results show that the surface of SU316L coated with F-DLC film could obviously reduce the number of adherent platelets and dramatically relieves the deformation of platelets, leading to a ratio of higher albumin to fibrinogen adsorption higher than that with using the SU316L substrates, which indicates that the SU316L coated with F-DLC film can improve the blood compatibility. The film has the highest ratio of albumin to fibrinogen adsorption and the best hemocompatibility when the ratio of gas flow is 2 ∶1. Furthermore, the measurements of the contact angle, the surface energy of films and FTIR spectra show that the ratio of albumin to fibrinogen adsorption and the hemocompatibility of F-DLC coated SU316L depend on the surface energy (hydrophobic nature) of films and the quantity of -CFx bonds (the ratio of F/C) contained in film. The modulating of blood compatibility of the films can be realized by the control of the ratio of source gas flow.