Antibacterial Cr–Cu–O films prepared by reactive magnetron sputtering

Antimicrobial Nanostructured Coatings: A Gas Phase Deposition and Magnetron Sputtering Perspective

“…It is interesting to note that such films composed of a single element present good adhesion, as shown by the ASTM D3359 cellophane tape test on hard and flexible substrates. On the other hand, the mixing into the coating of elements needed to obtain killing activity against both GP and GN strains has raised the issue of the coating mechanical stability [44,56,[116][117][118]. Musil et al [44,118] suggested that in this kind of thin film, the relative content of the most efficient antibacterial metals, Ag and Cu, needs to be between 10% and 30%, and this almost always results in a strong reduction of its hardness and in a poor mechanical stability, in particular if the film thickness is on the order of hundreds of nm.…”

“…On the other hand, the mixing into the coating of elements needed to obtain killing activity against both GP and GN strains has raised the issue of the coating mechanical stability [44,56,[116][117][118]. Musil et al [44,118] suggested that in this kind of thin film, the relative content of the most efficient antibacterial metals, Ag and Cu, needs to be between 10% and 30%, and this almost always results in a strong reduction of its hardness and in a poor mechanical stability, in particular if the film thickness is on the order of hundreds of nm. This is a major drawback, since many practical applications of antibacterial coatings on contact surfaces of rigid or flexible substrates require a long lifetime, and therefore hardness and resistance to wear [56,116,117].…”

“…Moreover, when such coatings are deposited on flexible substrates, they easily crack and/or delaminate due to the residual stress resulting from the growth mode (for some reviews on thin film growth modes and on the effect on surfaces, see for instance [119,120]). This issue has recently been investigated for antibacterial films prepared by reactive magnetron sputtering for Cr-Cu-O [44,118], Al-Cu-N [44,114] and Zr-Cu-N [121], where the influence of Cu content on the mechanical and bactericidal properties of the film have been measured. The mechanical characteristics measured through Vickers tests were the film hardness H, defined as its resistance to local plastic deformation [122], the elastic recovery We, defined as the fraction of a given deformation of a solid which behaves elastically [123], the Young's modulus E and the effective Young's modulus E* = E(1 − ν 2 ), where ν = Poisson ratio has been obtained by mechanical indentation.…”

Flexible antibacterial Al–Cu–N films

“…the bacteria colony forming units (CFUs), grown from the suspension which was in contact with the surface of the reference Si substrate (without Al-Cu-N film) and B is the number of bacterial colonies grown from the suspension which was in contact with the Al-Cu-N film covering the surface of Si substrate. More details are given in the reference [29]. The antibacterial efficiency E k was evaluated in the daylight for various contact times t (0.5, 1, 3 and 5 h) and in the dark for the contact time of t = 5 h only.…”

“…For this purpose the films containing silver Ag [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and copper Cu [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] were developed. It was found that both kinds of films efficiently kill bacteria if the content of Ag or Cu is higher than a minimum value, which usually is of about 10 at.% or greater.…”