| Abstract [eng] |
The surfaces of materials used in medicine have to meet certain requirements: they must be hard, mechanically sturdy, resistant to friction, wear, and corrosion, hydrophilic, chemically inert, and must exhibit good hemocompatibility and biocompatibility. Surfaces must be resistant to the adhesion of harmful bacteria and platelets that can cause thrombosis but should not adversely affect the adhesion of human tissue cells. This is especially important for materials that are used to make medical implants. Raw materials generally do not have these properties, their mechanical hardness, hemocompatibility and biocompatibility are insufficient, so their surfaces have to be modified. One of the ways to provide the required properties to materials is coating them with amorphous carbon coatings, especially diamond-like carbon coatings that exhibit the best mechanical properties. In this work, the influence of amorphous carbon coatings on the surface properties of stainless steel, polyether ether ketone, polycaprolactone, polyethylene terephthalate and glass was investigated. Analysis of amorphous carbon coatings deposited on silicon by plasma enhanced chemical vapor deposition revealed that the most diamond-like coatings were obtained using acetylene gas flow of 11.7 cm3/min. Amorphous carbon coatings were deposited on stainless steel, polyether ether ketone, polycaprolactone, polyethylene terephthalate and glass by the same method, using acetylene gas flow of 11.7 cm3/min and discharge power of 100–400 W. Ellipsometry and Raman spectroscopy revealed that hard diamond-like carbon coatings with high refractive indices and low extinction coefficients and ID/IG ratios were deposited on stainless steel, polyether ether ketone, polyethylene terephthalate, and glass, meanwhile softer polymer-like or graphite-like carbon coatings with low refractive indices and high extinction coefficients were deposited on polycaprolactone. Carbon coatings reduced the ultraviolet and visible light transmittance of polyethylene terephthalate and glass. Carbon coatings irradiated with ultraviolet light for 45 minutes graphitized and further reduced the transmittance of polyethylene terephthalate and glass. Contact angle measurements revealed that carbon coatings increased the surface energy and hydrophilicity of all materials except for glass. Coatings caused the decrease of the surface energy of glass. It was observed that more graphite-like carbon coatings with lower refractive indices, higher extinction coefficients and ID/IG ratios caused a higher increase of the surface energy of materials than more diamond-like carbon coatings with higher sp3 content. Coatings irradiated with ultraviolet light for 45 minutes graphitized and their hydrophilicity and surface energy further increased. The obtained results have proven that amorphous carbon coatings effectively increase the surface energy and hydrophilicity of stainless steel and polymers, leading to better hemocompatibility and biocompatibility. Amorphous carbon coatings reduced the surface energy and hydrophilicity of glass which could be used to reduce the adhesion of dirt on medical containers and eyeglass lenses made of glass and make cleaning them easier. |
