(180k) Phase Transfer Catalyst -Functionalized Nanosheets for Emulsion Formation and Stabilization

Phase transfer catalyst (PTC) such as quaternary ammonium cations has been used to modify the surface of nanosheets. Synergistic effect between water dispersible nanosheets and an oil-soluble surfactant in emulsion formation and stabilization was investigated. The addition of nanosheet functionalized with bulky organic cation improved the stability of both oil-in-water and water-in-oil emulsions. This is contributed to the spontaneous adsorption of solid particles to the water-oil interface and the formation of Pickering emulsions. This was also verified by microfluidic experiments, where increasing frequency of coalescence was observed for water droplets containing higher nanosheet particle loadings. The use of PTC with shorter alkyl chain was much less effective in emulsion stabilization. This study demonstrates that selected PTC with the appropriate properties can be used to functionalize nanosheet surfaces to make stable emulsions. Our approach introduces a new surface modification scheme to control particle wettability and thus emulsion behavior and performance.