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In situ production of spherical aerogel microparticles
Publikationstyp
Journal Article
Date Issued
2010-10-12
Sprache
English
Author(s)
Institut
Volume
55
Issue
3
Start Page
1118
End Page
1123
Citation
Journal of Supercritical Fluids 55 (3): 1118-1123 (2011-01-01)
Publisher DOI
Scopus ID
Publisher
Elsevier Science
Due to their high surface area, low density, open pore structure and excellent insulation properties aerogels are intensively investigated since the past decades for a diverse range of applications. The current methods of silica aerogel production by supercritical extraction produce monolithic aerogels, where the sol is aged in molds and dried by extraction with supercritical CO2. Aerogels in the form of spherical microparticles would be beneficial for many applications, for instance, drug delivery for respiratory route; or as insulating materials. However, because of aerogel's mechanical properties, it is difficult, rather impossible, to obtain spherical microparticles by milling or crushing of the monolithic aerogels. This work presents a new method to produce biocompatible spherical aerogel microparticles using an emulsion technique (in situ production) followed by supercritical extraction of the resulted dispersion (gel-oil). Water in oil emulsion was produced by mixing the sol (dispersed phase) with a vegetable oil (continuous phase) followed by the gelation of the dispersed phase. The size distribution of the final gel particles was found to be influenced by agitation, surfactant concentration and sol:oil volume ratios. The gel-oil dispersion was subsequently extracted with supercritical CO2, Silica aerogel spherical microparticles with a surface area of 1100 m2g-1, pore volume of 3.5 cm3/g and different mean particle diameters ranging from 200 μm to a few millimeters were produced using the presented method.
Subjects
Emulsion
Silica aerogel
Spherical nanoporous microparticles
Supercritical extraction
DDC Class
530: Physik