Stöber synthesis

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Simplified representation of the hydrolysis and condensation reaction of tetraethoxysilane (TEOS) in the Stöber synthesis

The Stöber synthesis (sometimes also referred to as the Stöber method , the Stöber process or the Stöber method ) is a synthesis of monodisperse colloid suspensions of spherical silica nanoparticles named after Werner Stöber . The uniform particle size of these nanoparticles facilitates the interpretation of their physicochemical properties, the calibration of measuring devices or the interpretation of the physiopathological effects of colloids and aerosols .

synthesis

The controlled growth of spherical silica particles of uniform size occurs through the hydrolysis of silica esters and subsequent condensation of silica in alcoholic solutions, with ammonia being used to control the morphological properties. The particle sizes obtained are between about 0.05 and 2  micrometers in diameter.

Applications

Silicon dioxide produced with the Stöber synthesis is due to its monodispersity, i.e. due to the uniformity of its particle sizes, an ideal material for investigating colloidal phenomena. The particles are also used to deliver drugs in cell structures and in the manufacture of biosensors .

Nanoparticles according to the Stöber synthesis are used in catalysis due to their large surface area and their uniform, adjustable and highly ordered pore structures .

Highly effective thermal insulators known as aerogels can also be made using Stöber methods, and Stöber techniques have been used to make airgel systems without silica. With supercritical drying techniques, a Stöber silica airgel with a specific surface area of ​​700 m 2 · g −1 and a density of 0.040 g · cm −3 can be produced. NASA produced silica aerogels using the Stöber process for both the Mars Pathfinder and Stardust missions.

literature

  • Atul Tiwari, Mark D. Soucek: Concise Encyclopedia of High Performance Silicones . Wiley, Hoboken, 2014, ISBN 978-1-118-46965-1 .

Individual evidence

  1. ↑ Werner Stöber, Arthur Fink, Ernst Bohn: Controlled growth of monodisperse silica spheres in the micron size range. In: Journal of Colloid and Interface Science. 26, 1968, pp. 62-69, doi: 10.1016 / 0021-9797 (68) 90272-5 .
  2. ↑ Liane M. Rossi, Lifang Shi, Frank H. Quina, Zeev Rosenzweig: Stöber Synthesis of Monodispersed Luminescent Silica Nanoparticles for Bioanalytical Assays. In: Langmuir. 21, 2005, pp. 4277-4280, doi : 10.1021 / la0504098 .
  3. ↑ UPM Ashik, WMA Wan Daud: Stabilization of Ni, Fe, and Co nanoparticles through modified Stöber method to obtain excellent catalytic performance: Preparation, characterization, and catalytic activity for methane decomposition. In: Journal of the Taiwan Institute of Chemical Engineers. 61, 2016, pp. 247–260, doi : 10.1016 / j.jtice.2015.12.019 .