Novel thin-film nanocomposite membranes filled with multi-functional Ti3C2Tx nanosheets for task-specific solvent transport

MXenes as an emerging class of 2D metallic carbide/carbonitrides materials have great potentials in designing and fabricating functional polymer composites. In this study, Ti3C2Tx as a representative MXene was employed to fabricate thin-film nanocomposite (TFN) membranes. The abundant surface groups (mainly OH) on Ti3C2Tx allowed facile modification, and thus evenly functionalized nanosheets were obtained. Four functional groups were grafted on Ti3C2Tx surface respectively, which was found to strongly affect the affinity towards solvent molecules and further determine the solvent transport properties of membranes. Interestingly, the functional groups on Ti3C2Tx, namely NH2, COOR, C6H6, and C12H26, could effectively enhance the flux for isopropanol, ethyl acetate, toluene, and n-heptane, respectively, no matter the polymer matrix was hydrophilic or hydrophobic. This finding indicated that the task-specific function of Ti3C2Tx could be distinctly transferred to TFN membranes. Moreover, the nanosheets effectively blocked the permeation of solute molecules, resulting in high rejection ability.