Synthesis and characterization of silver-rich coatings loaded with functionalized clay nanoparticles
A synthetic exfoliated nanoclay smectite type, Laponite® S482, was incorporated as a functionalized load in a silica hybrid matrix synthesized by the sol–gel route. The previous functionalization was carried out through a “grafting” reaction with (3-glycidoxypropyl)trimethoxysilane (GPTMS) assisted by ultrasonic dispersion. The precursor sols were synthesized by acid-catalyzed hydrolytic condensation between tetraethoxysilane (TEOS) and functionalized GPTMS, a silver ions source was added in order to obtain a coating material with controlled silver releasing properties. Coatings were obtained by “dip-coating” on different substrates. Structural characterization of the coatings was conducted by SAXS and SEM-EDS, the results revealed a complex silica matrix with intercalated nanoclays, an organic fraction and a homogeneous content of Ag+. The electrochemical characterization was realized by EIS tests on stainless steel coated substrates AISI 316L type; the results showed good barriers properties and a high integrity of the coatings loaded with nanoclay. The evolution of the release of Ag+ ions was studied by XRF, through exposing the coatings to a leaching process at steady state and determining the residual content of Ag within the coat at different immersion times. It was found that the addition of 1.5 wt. % of clay, in respect to condensed silica, decreased the initial diffusion rate of Ag+ ions at near the half part, allowing its potential use in the development of antibacterial coatings with longer terms of life.
KeywordsSol–gel Nanoclays Silver ions Hybrid coating Silver release
Authors want to acknowledge the Argentine National Council of Scientific and Technical Researches (CONICET, PIP 2012-0434) and the National Synchrotron Light Laboratory of Brazil (LNLS, Project 6780/10, proposal D11A-SAXS1-15291) for the financial supports. In addition, Mr. Martín E. Lere is gratefully acknowledged for his helpful technical collaboration.
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Conflict of interest
The authors declare that they have no conflict of interest.
- 8.Joncoux-Chabrol K, Bonino JP, Gressier M et al. (2012) Improvement of barrier properties of a hybrid sol–gel coating by incorporation of synthetic talc-like phyllosilicates for corrosion protection of a carbon steel. Surf Coat Technol 206:2884–2891. https://doi.org/10.1016/j.surfcoat.2011.12.017 CrossRefGoogle Scholar
- 9.Santana I, Pepe A, Schreiner W, et al (2015) Hybrid sol–gel coatings containing clay nanoparticles for corrosion protection of mild steel. Electrochim Acta. https://doi.org/10.1016/j.electacta.2016.01.214
- 12.Crabtree JH, Burchette RJ, Siddiqi RA et al. (2003) The efficacy of silver-ion implanted catheters in reducing peritoneal dialysis-related infections. Perit Dial Int 23:368–374Google Scholar
- 18.Qin H, Cao H, Zhao Y et al. (2014) In vitro and in vivo anti-biofilm effects of silver nanoparticles immobilized on titanium. Biomaterials 35:9114–9125. https://doi.org/10.1016/j.biomaterials.2014.07.040 CrossRefGoogle Scholar
- 21.Orazem ME, Tribollet B (2008) Electrochemical Impedance Spectroscopy. Analysis. https://doi.org/10.1002/9780470381588
- 27.Akhavan O (2009) Silver nanocube crystals on titanium nitride buffer layer. J Phys D Appl Phys. https://doi.org/10.1088/0022-3727/42/10/105305
- 34.Liu C, Bi Q, Leyland A, Matthews A (2003) An electrochemical impedance spectroscopy study of the corrosion behaviour of PVD coated steels in 0.5 N NaCl aqueous solution: Part II.: EIS interpretation of corrosion behaviour. Corros Sci 45:1257–1273. https://doi.org/10.1016/S0010-938X(02)00214-7 CrossRefGoogle Scholar
- 43.Stobie N, Duffy B, McCormack DE et al. (2008) Prevention of Staphylococcus epidermidis biofilm formation using a low-temperature processed silver-doped phenyltriethoxysilane sol-gel coating. Biomaterials 29:963–969. https://doi.org/10.1016/j.biomaterials.2007.10.057 CrossRefGoogle Scholar