An Introduction to Sol-Gel Processing for Aerogels

Sol-gel processing facilitates effortless control of the composition, properties, and architecture of nanosystems. For this reason, the technology has been adapted as a popular route for the preparation of nanostructures. The process supports the preparation of intricate three-dimensional networks extended throughout a liquid phase (a gel) through the agglomeration of nanoparticles dispersed within a colloidal suspension (sol). In order to gain a greater understanding of the process before exploring the possible applications of the technology, this chapter outlines the activities involved in sol-gel processing. The formation of sol-gel materials is explained by briefly focusing on the mechanisms of hydrolysis and condensation, in addition to ageing and drying of wet gels. Sol-gel processing can be used to form a range of architectures from fibres and films to fine powders and monoliths, however this chapter will focus on sol-gel processing for aerogels specifically.