Fabrication of waterborne antibacterial/antistatic nanocomposite coatings at low content of Ti3C2 nanosheets via quaternary ammonium salt modification

MXenes have attracted significant attention due to their unique properties, including antibacterial property and electrical conductivity. However, the antibacterial performance of MXenes-based coatings strongly depends on their superficial distribution. In this study, Ti 3 C 2 nanosheets were modified with dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium (QAS) and further incorporated into waterborne epoxy coatings. Influence of modifier ratio on the distribution of QAS-modified Ti 3 C 2 nanosheets (Q-Ti 3 C 2 ) in coatings as well as on the antibacterial/antistatic performance of coatings was investigated. Appropriate amount of QAS (i.e., 10 %) for modification was critical to achieve high antibacterial performance at low content of Ti 3 C 2 nanosheets. The Q-Ti 3 C 2 embedded coating could get 99.4 % inhibition against E. coil and 100 % against S. aureus at 0.5 wt% loading. In contrast, the coating with unmodified Ti 3 C 2 only exhibited antibacterial rate of 85.3 % and 87.4 % for E. coil and S. aureus , respectively. The prominent antibacterial performance of Q-Ti 3 C 2 based coatings mainly results from the enriched residence of Ti 3 C 2 nanosheets at the upper layer of coatings and partially from the intrinsic antibacterial property of QAS. Additionally, the superficial distribution of Ti 3 C 2 nanosheets endowed the coatings with low surface resistance of 1.8 × 10 9  Ω, thereby conferring antistatic properties, and hence, facilitating antibacterial durability, even if the coating contains as low as 1 wt% Q-Ti 3 C 2 nanosheets. The nanocomposite coatings also exhibited better adhesion and high pencil hardness.