Skip to main content
. 2021 Jan 5;4(2):1136–1148. doi: 10.1021/acsanm.0c02771

Figure 1.

Figure 1

Silica synthesis methods and chemistry. (A) Schematics of the Stöber, AAC and WORM methods to synthesize silica nanospheres. In the Stöber method, silica growth happens in a basic alcoholic solution after the injection of TEOS. In the WORM method, silica growth takes place by the diffusion of TEOS from the oil phase into the basic water droplets of a water-in-oil reverse microemulsion. In the AAC method, silica growth takes place in an aqueous phase containing a basic amino acid from the slow diffusion of hydrolyzed TEOS from an unmixed, oil-like layer of nonhydrolyzed TEOS. (B) TEOS hydrolysis and condensation are two basic steps in silica growth for the Stöber, AAC, and WORM silica nucleation and growth processes. Basic media catalyzes both the condensation and hydrolysis steps. In fully condensed silica, each TEOS molecule has formed four siloxane bonds; however, all these procedures do not produce fully condensed silica.