Dissolution of Cu nanoparticles and antibacterial behaviors of TaN–Cu nanocomposite thin films

Previous study shows that TaN–Cu nanocomposite thin films can have both anti-wear and antibacterial properties. Both properties are dependent on the size and density of the surfaced Cu particles. The present study made an attempt to correlate the annealing conditions to the dissolving rate of Cu particles surfaced on TaN, which eventually decides the films' antibacterial performance. Cu powders with different particle sizes were first used to study the size effect on the Cu powders' dissolving behavior. The results were then used to understand the antibacterial performance of TaN–Cu nanocomposite thin films prepared under various conditions. It is found that the films with nano-sized Cu particles could respond faster in terms of antibacterial performance. When in contact with the TaN film, these Cu particles can have an even higher dissolving rate caused by galvanic effect. This implies that the annealed TaN–Cu nanocomposite thin films may have a different antibacterial function due to the difference in the particle size and density of surfaced Cu. Overall, the results imply that both short and long term antibacterial functions of these films can be controlled, provided that the emerged particle size and density of Cu are controlled.