Development of silver-containing diamond-like carbon for biomedical applications. Part I: Microstructure characteristics, mechanical properties and antibacterial mechanisms

Nanosilver containing diamond-like carbon films with different silver fractions were synthesized by the radio frequency magnetron sputtering using a single silver target in an atmosphere of Ar/CH₄ mixture. The nanocrystalline silver clusters spontaneously segregated within an amorphous diamond-like carbon matrix. The amorphous-to-crystalline phase transformation resulted in both the surface hardness and electrical resistivity of the composite films decreasing with increasing the silver cluster size. The enlarged cluster size also increased the film surface roughness and water contact angle. All the films exhibited an anti-bacterium rate of over 93%, which evidenced that applying these composite films to anti-bacterium surface treatment is effective.