APTES driven electrostatic assembled L-histidine loaded Ti3C2Tx MXene composite for enhanced corrosion resistance of epoxy coating

Two-dimensional Ti 3 C 2 T x MXene, with a large specific surface area, high chemical stability and excellent barrier properties, has become a promising of anti-corrosion filler in organic coatings. However, the poor dispersion and compatibility in organic coatings restrict its efficient application. To this end, L-histidine (L-His) corrosion inhibitor was grafted on the 3-aminopropyl triethoxysilane (APTES) functionalized Ti 3 C 2 T x MXene surface, under the electrostatic attraction between the carboxylate and protonated aminopropyl groups. The obtained APTES-Ti 3 C 2 T x MXene@L-His cannot only accelerate the dispersion of Ti 3 C 2 T x MXene filler, but also greatly promote the anti-corrosion property and service lifetime of coatings through combining the physical shielding effect of MXene laminate structure with active anti-corrosion function of L-His corrosion inhibitor. Results show that amino-functionalized Ti 3 C 2 T x MXene can maintain homogeneous in epoxy resin for 300 h, enhancing its dispersion in epoxy coating. Moreover, APTES-Ti 3 C 2 T x MXene@L-His composite can achieve the continuous release of L-His for 3000 min, and additional acid-base dual response property, the releasing rate of L-His is significantly accelerated in acidic or alkaline solutions. The total loading amount of L-His in APTES-Ti 3 C 2 T x MXene@L-His composite is about 3 %. Furthermore, the practical composite coating containing APTES-Ti 3 C 2 T x MXene@L-His also exhibits the excellent anti-corrosion and certain self-healing properties, such as its |Z 0.01 Hz| value remains above 10 10 Ω·cm 2 during the 40 d immersing in 3.5 NaCl solution, which is 3 orders of magnitude higher than that of pure epoxy coating. This work extends the great significance for Ti 3 C 2 T x MXene based composite coatings application of in the field of anti-corrosion.