A Sol and a Gel, What They Are?

Abstract

Giving a clear and widely accepted definition in chemistry and physics is always a pretty difficult task, especially because the frontier of science is continuously moving. Time is a good friend for science because knowledge accumulates and allows getting a wider and deeper understanding of nature; however, it is also more complicate organizing what are sometimes only fragments of a big puzzle. Definitions have also a historical development and they are modified according to new knowledge that accumulates or simply with a change of perspective. This short book is dedicated to sol- to -gel transition in oxides, and therefore the first mandatory step is a clear understanding of what a gel and a sol are.