Factors that affect Pickering emulsions stabilized by mesoporous hollow silica microspheres

Hypothesis: Classical (solid particles stabilized) Pickering emulsions have been widely studied due to the irreversible adsorption of solid particles at the oil-water interface. Mesoporous hollow silica micro -spheres (MHSMs) are promising stabilizers for Pickering emulsion owing to its larger specific surface area and lower apparent density. However, this type of Pickering emulsion has not attracted enough attention. The stabilization mechanism of Pickering emulsion by MHSMs has not been studied in detail yet. Experiments: Herein, stable Pickering emulsions were prepared using only MHSMs as stabilizers. In order to investigate its stabilization mechanism, the effect factors of size, shell thickness, wettability and con-centration of MHSMs, and oil/water ratio on the stability of Pickering emulsions were analyzed deeply. Findings: As a result, the stability of Pickering emulsion can be improved by MHSMs with smaller particle size and shell thickness. Also, MHSMs with the intermediate hydrophobicity and suitable oil/water ratio actually do favour for the stability of Pickering emulsion. As expected, the stability of Pickering emulsion can be enhanced by increasing the concentration of MHSMs in a certain range. The Pickering emulsions tend to achieve excellent stable state when the concentration of MHSMs is 1.25 mg/mL. All those results suggested that the stability of Pickering emulsions correlates directly to particle size, shell thickness, wet-tability and concentration of MHSMs, and oil/water ratio. This research paves a way for the fabrication of functional materials via Pickering emulsions. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study investigated the stabilization mechanism of Pickering emulsion using mesoporous hollow silica microspheres (MHSMs) as stabilizers. The results showed that smaller particle size and shell thickness of MHSMs can improve the stability of Pickering emulsion, and MHSMs with intermediate hydrophobicity and suitable oil/water ratio are favorable for stability. Increasing the concentration of MHSMs within a certain range can enhance the stability of Pickering emulsion, with the optimal concentration being 1.25 mg/mL. This research opens up possibilities for the fabrication of functional materials through Pickering emulsions.