DNA‐Passivated Ti3C2Tx MXene: Enhanced Oxidation Stability and Synergistic Flame Retardancy in Epoxy Composites

To date, the oxygen- and moisture-stability of transition metal carbides (MXenes) limit their use in various fields. Herein, we report on the enhanced oxidative stability of Ti ₃ C ₂ T _x MXene in aqueous environment by complexation of deoxyribonucleic acid (DNA) to the MXene. We found that the DNA improved the stability of MXene in aqueous dispersion, by collecting UV-vis spectroscopy data of MXene and MXene-DNA (MXD) aqueous dispersions for 31 days. Moreover, because DNA and MXene can act as flame retardants, we prepared MXD@EP composite material. Because of the structure of DNA, the passivation of DNA to MXene offers the acid source (phosphoric acid), carbon source (deoxyribose units), and blowing property (nitrogen-containing bases) to the MXene, and this makes MXD an effective flame retardant. Compared with EP, the addition of 1.5 wt% of MXD into EP increased a limiting oxygen index (LOI) value from 23.1–27.7%. In cone calorimeter test, 0.5 wt% content of MXD in EP showed 47.8%, 23.1% decline in peak heat release rate (pHRR), and total heat release (THR), respectively. Our findings highlight the susceptibility of MXene to oxidative failure and show that DNA not only protects the MXene nanosheets but also make flame retarding synergism with Ti ₃ C ₂ T _x MXene.