Poly(ionic liquid)-Promoted Solvent-Borne Efficient Exfoliation of MoS2/MoSe2 Nanosheets for Dual-Responsive Dispersion and Polymer Nanocomposites

摘要

Considering the great potential of layered transition-metal dichalcogenides in thin film photovoltaic, advanced composite materials, and biomedical applications, it is of high importance to have a highly efficient method for their generation in both aqueous and nonaqueous media. Here, we demonstrate a simple one-pot efficient exfoliation approach to prepare dispersion of single or few-layers MoS2 nanosheets by quick sonication in the presence of cationic poly(ionic liquids)s (PILs) in both aqueous and nonaqueous media at room temperature. These PILs are synthesized by simple conventional free radical polymerization from designed ionic liquid monomers. This method is extendable for efficient generation of MoSe2 nanosheets' dispersion in these solvents. Owing to the solubility in both water and organic solvents, cationic PIL molecules serve the dual purpose of an exfoliating-cum-stabilizing agent. PIL-stabilized nanosheets' dispersions are stable for more than two months at ambient temperature. The adsorption of PIL to the surface of MoS2 nanosheet converts them to responsive toward ions and temperature in aqueous medium. Additionally, MoS2 PIL nanosheets can easily be dispersed in water-soluble poly(vinyl alcohol) and nonaqueous-soluble poly(methyl methacrylate) matrices for making well-dispersed homogeneous nanocomposites and their dielectric properties are studied.