Effect of Tetraethoxy-silane (TEOS) Amounts on the Corrosion Prevention Properties of Siloxane-PMMA Hybrid Coatings on Galvanized Steel Substrates

Abstract

Siloxane-poly(methyl methacrylate) (PMMA) organic-inorganic hybrid coatings were deposited on galvanized steel by the dip-coating sol-gel technique. Anticorrosion properties, as well as the morphological, surface and structural features were studied. Hybrid coatings were synthesized from tetraethoxy-silane (TEOS) and methyl methacrylate (MMA) as inorganic and organic phases, respectively, linked by 3-metacriloxypropyl-trimethoxysilane (TMSM) as a coupling agent. The MMA/TMSM ratio was kept constant, whereas the four TEOS/TMSM ratios were varied. The characterization of coatings was assessed using several techniques such as Scanning Electronic Microscopy (SEM), Contact Angle, Fourier Transform Infrared (FT-IR), Open Circuit Polarization (OCP), Atomic Force Microscopy (AFM) and Electrochemical Impedance Spectroscopy measurements (EIS). The EIS results, which were obtained for the hybrid coatings, were discussed based on an electrical equivalent circuit used to adjust the experimental data. The results showed that the increasing the TEOS content caused increase in coating thickness, increased in the surface roughness and increased in the surface hydrophobicity. The film with the highest TEOS content presented the best electrochemical performance, more effective in protecting against corrosion.

Influence of silica nanoparticles on corrosion resistance of sol-gel based coatings on mild steel

“…Data was collected (for a duration of 1 h) at times of 1 h, 24 h and 48 h of exposure. All coated samples show a corrosion potential substantially higher than the bare steel (Q-panel), suggesting that these coatings have a barrier effect, in agreement with trends observed by other researchers [36,37].…”

Obtainment and Characterization of a Silicon alkoxides-based Coating Applied to a Substrate of Stainless Steel 316L for Use in Biomaterials

“…According to Kunst et al (2014) 26 , due to the excess of heat in the process of cure the number of reactions of silane reticulation increases, thus reducing its reactivity. This loss of reactivity is caused by the conversion of the silane groups in siloxanes.…”

Silane coatings of metallic biomaterials for biomedical implants: A preliminary review

“…As such, silane films with greater packing densities will physically obstruct electrolyte from reaching the underlying implant, and those with more hydrophobic nature will reduce wetting and contact with aqueous corrosive media. Indeed, researchers have seen greater incidences of corrosion on coatings of more hydrophilic silanes, such as γ‐APS and TEOS . Van Ooij et al recently provided an overview of the effects of different functionalized silanes on corrosive resistance .…”

“…Indeed, researchers have seen greater incidences of corrosion on coatings of more hydrophilic silanes, such as g-APS and TEOS. 55,56 Van Ooij et al recently provided an overview of the effects of different functionalized silanes on corrosive resistance. 54 While literature of silane corrosion protection in conditions representative of more common applications, like aqueous NaCl or Na 2 SO 4 , is abundant in literature, 54,57 that in a physiological environment has only begun to see examination.…”