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Publisher: Basel : MDPI × Subject: coating ×

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Now showing 1 - 3 of 3
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    Straightforward Approach for Preparing Durable Antibacterial ZnO Nanoparticle Coatings on Flexible Substrates
    (Basel : MDPI, 2022) Šutka, Andris; Mežule, Linda; Denisova, Viktorija; Meier-Haack, Jochen; Kulkarni, Akshay; Bitina, Sanda; Smits, Krisjanis; Vihodceva, Svetlana
    Flexible antibacterial materials have gained utmost importance in protection from the distribution of bacteria and viruses due to the exceptional variety of applications. Herein, we demonstrate a readily scalable and rapid single-step approach for producing durable ZnO nanoparticle antibacterial coating on flexible polymer substrates at room temperature. Substrates used are polystyrene, poly(ethylene-co-vinyl acetate) copolymer, poly(methyl methacrylate), polypropylene, high density polyethylene and a commercial acrylate type adhesive tape. The deposition was achieved by a spin-coating process using a slurry of ZnO nanoparticles in toluene. A stable modification layer was obtained when toluene was a solvent for the polymer substrates, namely polystyrene and poly(ethylene-co-vinyl acetate). These coatings show high antibacterial efficiency causing >5 log decrease in the viable counts of Gram-negative bacteria Escherichia. coli and Gram-positive bacteria Staphylococcus aureus in 120 min. Even after tapping these coated surfaces 500 times, the antibacterial properties remained unchanged, showing that the coating obtained by the presented method is very robust. In contrast to the above findings, the coatings are unstable when toluene is not a solvent for the substrate.
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    Development of a Metal-Based Lightweight Approach Consisting of Cold-Formable Magnesium Sheets in Combination with a Multi-Purpose Powder Coating System
    (Basel : MDPI, 2022) Victoria-Hernández, José; Scholz, Peter; Vakulenko, Serhii; Gedan-Smolka, Michaela; Tuschla, Marcel; Letzig, Dietmar; Kwiatkowski, Lech
    This paper will give an overview about the development of a material system, which consists of a novel formable magnesium alloy that is provided with an effective corrosion protection coating. The corrosion protection is to be realized in the form of a forming stable powder coating, which can be applied in the coil coating process. To improve the tribological properties, additional additives are added to the powder coating. Within this paper, first results concerning tribological and forming behavior of the new lightweight material system are given. For the benchmark, the results are compared with commercially available AZ31 Mg alloy.
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    Designing Gallium-Containing Hydroxyapatite Coatings on Low Modulus Beta Ti-45Nb Alloy
    (Basel : MDPI, 2023) Vishnu, Jithin; Voss, Andrea; Hoffmann, Volker; Alberta, Ludovico Andrea; Akman, Adnan; Shankar, Balakrishnan; Gebert, Annett; Calin, Mariana
    Low-modulus β-type Ti-45Nb alloy is a promising implant material due to its good mechanical biocompatibility, non-toxicity, and outstanding corrosion resistance. Its excellent chemical stability brings new challenges to chemical surface modification treatments, which are indispensable for both osteogenesis and antibacterial performance. Coatings containing metal ions as anti-microbial agents can be an effective way to reduce implant-associated infections caused by bacterial biofilm. Gallium ion (Ga3+) has the potential to reduce bacterial viability and biofilm formation on implant surfaces. In this study, a novel two-step process has been proposed for Ga3+ incorporation in hydroxyapatite (HAP) to develop bioactive and antibacterial surfaces on Ti-45Nb alloy. For the generation of bioactive surface states, HAP electrodeposition was conducted, followed by wet chemical immersion treatments in gallium nitrate (1 mM). Different buffers such as phosphate, sodium bicarbonate, ammonium acetate, and citrate were added to the solution to maintain a pH value in the range of 6.5–6.9. Coating morphology and HAP phases were retained after treatment with gallium nitrate, and Ga3+ ion presence on the surface up to 1 wt.% was confirmed. Combining Ga and HAP shows great promise to enable the local delivery of Ga3+ ions and consequent antibacterial protection during bone regeneration, without using growth factors or antibiotics.