Development of an in-situ chitosan‑copper nanoparticle coating by electrophoretic deposition

Ehsan Tabesh, Hamidreza Salimijazi, Mahshid Kharaziha, Mohamad Mahmoudi, Mehdi Hejazi

The aim of this study was to develop a chitosan‑copper nanocomposite coating on stainless steel 316L to improve the antibacterial properties and corrosion resistance of the substrate. After in-situ synthesizing of chitosan-modified Cu nanoparticles, electrophoretic deposition was utilized to deposit chitosan‑copper nanocomposite coatings consisting of various amounts of Cu nanoparticles. Moreover, the role of various deposition parameters such as time and voltage on the coating properties was investigated. Physical and chemical properties of the synthesized Cu nanoparticles and the nanocomposite coatings were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), coupled with the Energy-Dispersive Spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The corrosion resistance of coatings was measured by electrochemical measurements such as tafel and electrochemical impedance spectroscopy (EIS) tests. The antibacterial properties of nanocomposite coatings were analyzed using several Gram-positive and Gram-negative microorganisms, including methicillin-resistant Staphylococcus aureus and Escherichia coli. Results confirmed that Cu nanoparticles were synthesized with an average size of 11 ± 6 nm. Moreover, the incorporation of 0.5 wt% copper nanoparticle in the chitosan coating under 20 V and 5 min conditions resulted in the formation of uniform and crack-free nanocomposite coating with a thickness of about 17 μm. Results confirmed a significant improvement in the antibacterial activity and corrosion resistance of 316L stainless steel substrates. In conclusion, chitosan‑copper nanocomposites could be considered as a good candidate for increasing the antibacterial properties and corrosion resistance to prevent infections in biomaterials applications.