CVD Elaboration of Nanostructured TiO₂‐Ag Thin Films with Efficient Antibacterial Properties

Abstract

Nanostructured TiO 2 -Ag composite coatings are deposited by direct liquid injection metal-organic (DLI-MO) CVD at 683 K in a one-step process. Silver pivalate (AgPiv) and titanium tetra-iso-propoxide (TTIP) are used as Ag and Ti molecular precursors, respectively. Metallic silver nanoparticles are co-deposited with anatase TiO 2 on stainless steel, glass, and silicon wafers. The silver particles are uniformly embedded in the oxide matrix through the entire film thickness. The influence of the growth conditions, including injection parameters, is investigated on the chemical, physical, and structural characteristics of the coatings as well as on their anti-bacterial activities. The bacterium Staphylococcus aureus is employed for anti-bacterial tests. The films are bactericidal, according to the JIS Z 2801 standard test performed in the dark, when they contain less than 1 at.-% of silver. Under UV irradiation they exhibit a photocatalytic activity which decays by increasing the silver content. As a result of this dual functionality, the TiO 2 -Ag nanocomposite coatings show promising potentialities as long-term anti-bacterial surfaces since selfcleaning can be achieved periodically under UV light in order to maintain an efficient anti-bacterial activity in the dark or in visible light.

Nanocomposite thin film of Ag nanoparticles embedded in amorphous Al 2 O 3 on optical sensors windows: Synthesis, characterization and targeted application towards transparency and anti-biofouling

“…Ag NPs were processed by direct liquid injection, DLI-CVD from silver pivalate (CH 3 ) 3 CC(O)OAg (namely AgPiv), by adapting a protocol reported in [17]. The precursor solution was prepared by mixing AgPiv (Lotus Synthesis) and a solution of mesytylene/dipropylamine (Sigma Aldrich) (90/10 vol.…”

“…Co-deposition was performed at 723 K for 31 min to reach submicrometric thickness (ranging from 300 nm to 200 nm for Q1 to Q4 respectively, estimated by reflectometry measurements). This temperature is suitable for the deposition of both Ag NPs [17] and a-Al 2 O 3 films [20] from the two selected precursors. Prior codeposition, a thin film of pure a-Al 2 O 3 was deposited on the substrates surface with the aim to enhance the adhesion, by feeding the reactor with ATI and the dilution gas for 5 min, in the previously defined conditions.…”

“…Such films, processed from aluminum tri-isopropoxide, ATI contain a large percentage of penta-coordinated Al 3+ ions, as was demonstrated by 27 Al nuclear magnetic resonance, NMR spectroscopy [16]. The group also investigated CVD processes of nanostructured composite coatings containing Ag NPs embedded in a titanium dioxide matrix [17].…”

Inorganic hydrophobic coatings: Surfaces mimicking the nature

“…The bactericide characteristics of the coatings were measured according to the standard JIS Z 2801, where the number of Staphylococcus aureus bacteria before and after an ideal life bacteria environment treatment [32] is taken into account.…”

Synthesis and Antibacterial Properties of ZnO:Ag Films Prepared from a TritonMR Containing Solution

“…In particular, antimicrobial thin films had attracted great interest since survival of microorganisms on surfaces can result in the spread of the diseases [3], and the risk hazard upon inhalation antibacterial compounds it´s minimal [4] compared with the powders-based systems. For example, several antimicrobial semiconductor materials, like TiO 2 had been synthetized doped with Ag [5,6], Cu [7] or Pt [8]. A different approach is the use of a relatively low-cost ZnO matrix, since it has been largely demonstrated its capacity to inhibit the growth of microorganisms, as well to act as a high-range antibacterial agent [9 ,10].…”