Electrophoretic deposition of nanostructured TiO₂/alginate and TiO₂-bioactive glass/alginate composite coatings on stainless steel

Abstract

Two alginate (Alg) based composite coatings on stainless steel AISI 316L substrates, one containing titania nanoparticles (n-TiO 2 ) and another one a mixture (50/50 wt-%) of n-TiO 2 and bioactive glass (BG), intended for biomedical applications, were developed by electrophoretic deposition (EPD) from ethanol/water suspensions. Different n-TiO 2 (2-10 g L 21 ) and BG (1-5 g L 21 ) contents were studied for a fixed alginate concentration (2 g L 21 ), and the properties of the electrophoretically obtained coatings were characterised. Coatings with high ceramic content (up to 67 vol.-%) were obtained. The presence of BG particles improves the mechanical properties of the coatings by increasing the adhesion to the substrate and also accelerates the formation of hydroxyapatite after immersion of the coatings in simulated body fluid. The electrochemical behaviour of the coated substrates, evaluated by polarisation curves in Dulbecco's modified eagle medium at 37uC, confirmed the corrosion protection function of the novel EPD coatings. The present polymer-ceramic composite coatings belong to an emerging family of bioactive, compliant coatings that are promising for a range of biomedical applications.

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

“…It could be a result of higher stiffness of coatings with higher ceramic phase/polymer ratio. The decrease of the adhesion to the stainless steel substrate of the polymer (alginate)/TiO 2 coatings associated with the increase of the ceramic phase fraction was observed also by Cordero-Arias and others [28]. They have postulated that the higher oxide/polymer ratio in those coatings influences the decrease of the polymer binding effect thus results in the intensification of brittle cracks in scratch tests.…”

Electrophoretic deposition of nanoscale TiO2: technology and applications

“…10 shows SEM images of the surface and cross-section of the coatings obtained with different titania contents. In a similar study [150], the authors obtained biocompatible coatings containing titania P25, bioactive glass microparticles and alginate, another well-known biopolymer, from a water/ethanol suspension (60 vol.% water) at 7 V and depositing for 1 min. In this case, the presence of titania was considered to strengthen the coatings after testing the samples in Simulated Body Fluid (SBF) for 7 days, while the bioactive glass particles were used to speed up hydroxyapatite (HA) formation on the surface [150].…”

“…In a similar study [150], the authors obtained biocompatible coatings containing titania P25, bioactive glass microparticles and alginate, another well-known biopolymer, from a water/ethanol suspension (60 vol.% water) at 7 V and depositing for 1 min. In this case, the presence of titania was considered to strengthen the coatings after testing the samples in Simulated Body Fluid (SBF) for 7 days, while the bioactive glass particles were used to speed up hydroxyapatite (HA) formation on the surface [150]. Seuss et al [151] deposited titania nanoparticles in combination with polyether ether ketone (PEEK) using two different solid contents (4 and 6 wt.%) and four different PEEK to titania ratios (2:1, 3:1, 4:1, and 5:1) in ethanol based suspensions.…”

Electrophoretic deposition of ZnO/alginate and ZnO-bioactive glass/alginate composite coatings for antimicrobial applications

“…An interesting polymer for fabrication of organic/inorganic composite coatings with potential biomedical applications is alginate [36], which has been used only to a limited extent in combination with EPD to produce bioactive coatings [28,31,36,37]. Alginate is a natural polysaccharide which, due to its low toxicity and biocompatibility [38][39][40], has been studied for different applications, e.g.…”