Although the current aerogel market growth rate is driven almost exclusively by thermal insulation, aerogels may also be attractive for acoustic applications. Our group has started systematic efforts to realize the potential of silica aerogels and its composites as acoustic materials. Because of the wide variety of aerogel composites available (polymers, textiles, renders), each type of composite requires its own detailed experimental and theoretical investigations, but the acoustic properties nevertheless have a strong relation to the structural and physical properties of the aerogel itself, e.g. pore size inside the structure and granule/particle size. Aerogels have been analyzed predominantly for their sound absorption properties, especially with the impedance tube device, but there is also interest for structure-born noise insulation applications. However, the question about how well an aerogel-based product can perform as acoustic insulation, if it is optimized for its acoustic properties first and foremost, remains open for now, and demands for more systematic analyses of acoustic properties of the different polymer-based aerogels and their composites.

More information can be achieved in our recent review paper on the acoustic properties of the silica aerogels and their composites [1].