Mechanochemical exfoliation and functionalization of MoS₂ in one step: a quick click method

Chemical functionalization of molybdenum disulfide (MoS₂) is an effective tool to fine tune its physico-chemical properties. Typically, this process occurs in two steps: first the exfoliation of bulk MoS₂ and subsequently, the obtained layers are functionalized with the desired molecular fragment. However, a long time is required for the complete sequence. Herein we report the simultaneous exfoliation and functionalization of MoS₂ with different maleimides in short times (10 min) using mechanochemistry. The resulting few-layer functionalized MoS₂ materials are thoroughly characterized by TEM, AFM, Raman spectroscopy, DRIFT, XPS, and solid-state ¹³C-NMR, collectively confirming both the exfoliation to few-layer flakes (average thickness 5 ± 1 nm) and the formation of covalent S-C bonds. Critically, the choice of the maleimide functional group allows direct tuning of the dispersibility of the functionalized material in a range of green solvents, yielding stable dispersions in isopropanol, water, or ethyl acetate depending on the substituent. This rapid, scalable, and solvent-free approach opens a practical route to covalently functionalized MoS₂ powders for downstream applications.