solgelStöberprocesser

The Stöber process is a widely used sol-gel method for synthesizing silica (SiO2) particles with controlled sizes and narrow size distributions. It was first described by Werner Stöber, Arthur Fink, and Ernst Bohn in 1968. This process involves the hydrolysis and condensation of silicon alkoxides, typically tetraethyl orthosilicate (TEOS), in an alcoholic solution containing water and ammonia as catalysts.

The Stöber process begins with the hydrolysis of TEOS, where silicon alkoxide molecules react with water to form silanol groups (Si-OH). This is followed by condensation, where silanol groups react to form siloxane bonds (Si-O-Si), leading to the growth of silica particles. The size of the resulting particles can be controlled by adjusting the reaction parameters, such as the concentration of TEOS, water, ammonia, and the type of alcohol used. Generally, higher concentrations of ammonia and water lead to larger particles, while higher concentrations of TEOS result in smaller particles.

The Stöber process is known for producing spherical, monodisperse silica particles with sizes ranging from tens of nanometers to several micrometers. The particles can be functionalized with various organic or inorganic molecules, making them useful for a wide range of applications, including catalysis, drug delivery, and materials science. Additionally, the Stöber process can be modified to synthesize other metal oxide particles, such as titania and zirconia, by using appropriate metal alkoxides.