Langmuir-Like Adsorption Behavior of Amine Ligand for Surface Chemistry of MXene

Surface chemistry is important to compresence the stability of oxidation and dispersion of MXene in different organic media, thereby expanding its potential applications. Amine ligands is a potential candidate to modify the surface of MXene nanosheets due to strong interaction between Amine functionalities and MXene surface. Among those, Oleylamine (OAm) is a promising ligand due to its amine functionalities and commercial availability. The OAm is grafting onto MXene by covalent bonds through nucleophilic reactions and hydrogen bonding at room temperature. Furthermore, the OAm develop monolayer on MXene surface behavior by Langmuir-like adsorption. It is finely confirmed by that the slope decreases as the OAm concentration (C_l) increases in coverage vs C_l. The monolayer formation occurs in two distinct steps: a lying-down phase followed by an ordered monolayer. The OAm grafted MXene nanosheets (OAm-MX) represent highly stable dispersion in various organic solvents including non-polar solvents, as well as excellent oxidation stability. This be attributed to the hydrophobic properties and steric stabilization induced by the long alkyl chain of OAm on the MXene surface. Moreover, the OAm-MX nanosheets was facially assembled by solution process on the various substrate, demonstrating enhanced coating performance. Therefore, this study provides key comprehension of the adsorption behavior and interaction between amine ligands and MXene nanosheets for the surface chemistry of MXene.