Novel fabrication of stable Pickering emulsion and latex by hollow silica nanoparticles.

Hypothesis: In conventional Pickering emulsions, solid nanoparticles are usually employed as stabilizers. However, hollow nanoparticles are desirable candidates for the stabilization of Pickering emulsion and latex due to their strong adsorption property and low density stemming from the hollow cavity structure.

Experiments: In order to investigate the superiority of hollow silica nanoparticles in stabilizing emulsions, Pickering emulsion and polyacrylate latex were fabricated using hollow silica nanoparticles as stabilizers. For comparison purposes, oil/water emulsions and polyacrylate latices were prepared using sodium dodecylsulfate or silica nanoparticles as stabilizers, also they were prepared without the stabilizer.

Findings: The results showed that the stabilizing capability of hollow silica particles was comparable to surfactants and superior to conventional silica nanoparticles. Irreversible adsorption and effective mechanical barrier of hollow silica nanoparticles at the surface of latex particles were responsible for the outstanding emulsifying property and stability. Furthermore, the low density of hollow silica nanoparticles imparted by their cavity structure was the primary reason for the fabrication of stable Pickering emulsion and latex. This work broadens our understanding of the factors influencing the stability of Pickering emulsion and latex.