Electrophoretic Deposition of Chitosan/h-BN and Chitosan/h-BN/TiO2 Composite Coatings on Stainless Steel (316L) Substrates

Abstract

This article presents the results of an experimental investigation designed to deposit chitosan/hexagonal boron nitride (h-BN) and chitosan/h-BN/titania (TiO2) composites on SS316L substrates using electrophoretic deposition (EPD) for potential antibacterial applications. The influence of EPD parameters (voltage and deposition time) and relative concentrations of chitosan, h-BN and TiO2 in suspension on deposition yield was studied. The composition and structure of deposited coatings were investigated by FTIR, XRD and SEM. It was observed that h-BN and TiO2 particles were dispersed in the chitosan matrix through simultaneous deposition. The adhesion between the electrophoretic coatings and the stainless steel substrates was tested by using tape test technique, and the results showed that the adhesion strength corresponded to 3B and 4B classes. Corrosion resistance was evaluated by electrochemical polarization curves, indicating enhanced corrosion resistance of the chitosan/h-BN/TiO2 and chitosan/h-BN coatings compared to the bare stainless steel substrate. In order to investigate the in-vitro inorganic bioactivity, coatings were immersed in simulated body fluid (SBF) for 28 days. FTIR and XRD results showed no formation of hydroxyapatite on the surface of chitosan/h-BN/TiO2 and chitosan/h-BN coatings, which are therefore non bioactive but potentially useful as antibacterial coatings.

Electrophoretic deposition of nanoscale TiO2: technology and applications

“…Zhang and Kwok [68] also observed an improvement of the mechanical properties of HA-based coatings when a three-component coatings (containing needle-shaped hydroxyapatite (HA), CNTs, and TiO 2 nanoparticles) was prepared by cathodic co-deposition on Ti6Al4 V. According to their results, HA coatings reinforced with 10% titania and 5% CNTs presented the hardest surface (991HV) without microcracking as well as the highest adhesion strength (12.6 MPa). Raddaha et al [152] prepared three-component composite coatings by co-deposition of titania P25 with hexagonal boron nitride (hBN) and chitosan. In their study, they consider the influence of titania nanoparticles on the corrosion resistance of the metal substrates and observed that the corrosion resistance of the coatings containing the three components was superior than that of a hBN/chitosan (TiO 2 -free) composite coating, meaning that titania nanoparticles have a positive effect in preventing the corrosion of the substrate.…”

Carbon nanotube-based coatings on titanium

“…16,17 Layer's mechanical, electrochemical and biological properties were investigated. The results were compared with those obtained for unmodified titanium surface.…”

Electrophoretic deposition of nc-TiO2/chitosan composite coatings on X2CrNiMo17-12-2 stainless steel

“…In case of chitosan, the suspension is stable in range of pH from 3.0 to 4.0, where the zeta potential takes Fig. 1 [20,23]…”

“…Chitosan is a polysaccharide, produced by deacetylation of chitin, which has a proven biocompatibility and antibacterial properties [11]. TiO 2 deposition on metal surface can be executed by use of many techniques, such as plasma spray technique [12,13], sol -gel [14,15], micro arc oxidation [16,17] and electrophoretic deposition (EPD) [18][19][20][21]. Chitosan, as biopolymer, is destroyed by high temperature.…”

“…In case of TiO 2 deposition from suspensions containing acetone or acetylacetone [23] may be used. It is also possible to use water and ethanolwater suspensions [18][19][20], what is very important for biomedical applications, because they are less toxic. In the case of deposition of chitosan the most commonly used solvents are water or water-ethanol mixture.…”