Zinc-doped silica/polyaniline core/shell nanoparticles towards corrosion protection epoxy nanocomposite coatings

Commercial paints and coatings can serve as a protective barrier for metallic substrates in a corrosive environment. A considerable variety of nanostructures can be embedded in a polymeric coating to achieve both barrier and active protection. This research aims to elucidate the role of polyaniline (PANI) as an active poly-electrolyte modifier for the surface modification of mesoporous silica nanoparticles (MSNs) doped with zinc cations (Zn2+). To characterize the samples, we employed different techniques, including field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), N-2 adsorption-desorption, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), inductively coupled plasma optical emission spectroscopy (ICP-OES), rheometric mechanical spectroscopy (RMS), differential scanning calorimetry (DSC), tensile, and electrochemical impedance spectroscopy (EIS). Characterization of PANI-MSNs proved the formation of PANI shells onto the surface of silica cores, and pH triggered the release of Zn2+ at the alkaline condition. Enhancement in rheological, thermal, and mechanical characteristics revealed good dispersion and chemical interaction between PANI coated nanoparticles and the epoxy matrix. Moreover, epoxy nanocomposite coatings illustrated a dual barrier/active protection after 50 days of salt immersion.

Automated summary

Commercial paints and coatings are utilized to protect metallic substrates in corrosive environments, with nanostructures embedded in polymeric coatings for barrier and active protection. This research focused on the role of PANI as an active poly-electrolyte modifier for the surface modification of MSNs doped with Zn2+. Characterization techniques showed the formation of PANI shells on silica cores and the release of Zn2+ triggered by pH changes. The enhanced rheological, thermal, and mechanical characteristics of the PANI-coated nanoparticles in epoxy nanocomposite coatings demonstrated good dispersion and chemical interaction, leading to dual barrier/active protection properties.