New pickering emulsions stabilized by silica nanowires

• Both hydrophilic and amphiphilic silica nanowires were synthesized via a wet-chemical process.
• Pickering emulsions were prepared by use of the two types of silica nanowires.
• Emulsions stabilized by amphiphilic nanowires show exceptional stability for over 4 months.

In this work, oil-in-water and water-in-oil emulsions stabilized by hydrophilic and amphiphilic silica nanowires separately were investigated by scanning electron microscopy (SEM), optical microscopy and visual observation. The effects of length, concentration and wettability of the nanowires on the stabilization of the emulsion were investigated. The hydrophilic silica nanowires of 10 μm length can be used to prepare stable oil-in-water emulsions, with a network forming on the surface of the emulsion droplet is believed to be beneficial for the emulsion stability; whereas, the amphiphilic silica nanowires of all three lengths (1.5, 2.5 and 5 μm) can produce water-in-oil emulsions stable for at least 4 months, and it was found that increasing either the length or concentration of silica nanowires resulted in the enhancement of the stabilization of emulsions by nanowires. Phase inversion from oil-in-water to water-in-oil can be easily achieved by increasing the oil volume fraction in the amphiphilic silica nanowire stabilized emulsions.

Pickering emulsions stabilized by hydrophilic and amphiphilic silica nanowires separately were prepared. The effect of length and concentration of the nanowires, and oil/water volume ratio on the stability of the emulsion were investigated.Figure optionsDownload as PowerPoint slide