Determination of the shell growth direction during the formation of silica microcapsules by confocal fluorescence microscopy

• Published in: Journal of materials chemistry. B, Materials for biology and medicine Vol. 3; no. 39; pp. 7745 - 7751
• Main Authors: van Wijk, Judith, Salari, Joris W. O, Meuldijk, Jan, Klumperman, Bert
• Format: Journal Article
• Language: English
• Published: England 21.10.2015
• Subjects: Biology; Confocal; Diffusion; Emulsions; Fluorescence; Formations; Microscopy; Precursors; Silicon dioxide
• ISSN: 2050-750X; 2050-7518
• DOI: 10.1039/c5tb01232e

A novel procedure was developed to determine the direction of silica growth during the formation of a silica shell around aqueous microdroplets in water-in-oil Pickering emulsions. Two fluorescently labeled silica precursors were added consecutively and the resulting microcapsules were visualized via confocal fluorescence microscopy, allowing the conclusion that the locus of reaction moves in the positive radial direction, i.e. from the inside to the outside. A consequence of the growth direction is that water has to diffuse through the shell to participate in the reaction on the outer surface of the shell. A novel procedure was developed to determine the direction of silica growth during the formation of a silica shell around aqueous microdroplets in water-in-oil Pickering emulsions, and it was found that the shell grows from the inside to the outside.