Nanostructures: Designed by nature - a brief history of Synthetic Amorphous Silica (SAS).

Synthetic Amorphous Silica (SAS) has been produced and marketed since the early 1940s and can be regarded as a nanomaterial (NM) or more precisely as a nanostructured material since the first production even though the term 'nanomaterial' was not defined back then. Early publications often use the term 'milli-micron' instead of 'nanometer'. During this long history, SAS found its way into an increasing number of applications. Nowadays it is one of the commercially most relevant NMs, which is produced on a million-ton scale worldwide. It is an essential ingredient in many everyday applications, such as toothpaste, food, animal feed, pharmaceuticals, and tires, as well as in innovative advanced technologies for decarbonization like in batteries or windmill blades. The present paper from Evonik Industries AG reviews the history of innovation and production of SAS with a focus on pyrogenic silica, precipitated silica, and silica gel.