Hybrid MXene (Ti₃C₂T_x)/polyaniline nanosheets as additives for enhancing anticorrosion properties of Zn-epoxy coating

Corrosion is a problematic and costly issue in various technological fields, especially in marine, automobile, rail, and building industries. To effectively cope with this issue, transition-metal carbides (Ti₃C₂T_x), a 2-dimensional conductive material, functionalized with polyaniline (PANI) have been developed and applied as anticorrosion additive in a Zn-epoxy coating, due to its high specific surface area, excellent electronic conductivity and ease of surface modifications. Ti₃C₂T_x functionalized with PANI (Ti₃C₂T_x/PANI) was fabricated via an in-situ polymerization of aniline monomer using ammonium persulphate initiator. The presence of crystalline PANI molecules in the interlayer and on the surface of Ti₃C₂T_x was reflected by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectrometer (SEM-EDX), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The formation of crystalline PANI in the interlayer of Ti₃C₂T_x created the conductive pathway for increased electrical conductivity and enhanced compatibility with the epoxy matrix. The Ti₃C₂T_x/PANI composites were sonicated into ultrathin nanosheets, dispersed in the Zn-epoxy resin, and applied as an anticorrosion coating on steel substrates. Their anticorrosion performance was evaluated using an accelerated immersion test in severe acidic solution. The inclusion of 2.0 wt% Ti₃C₂T_x/PANI into the Zn-epoxy coating showed lower amounts of corrosion products, water adsorption, and leached iron concentration than pure epoxy and the Zn-epoxy coatings, indicating an enhanced anticorrosion property of the developed composites.