Structural and acoustic properties of transparent chitosan aerogel

Abstract The first report on acoustic absorption properties of transparent biopolymer aerogel is provided. Cross-linked chitosan aerogel prepared by supercritical carbon dioxide drying has a homogeneous nanofibrous structure with mesopores, the major size of which decreases from ∼45 to ∼20 nm with increasing apparent density. The aerogel shows peak-shaped sound absorption profiles, regardless of the density. This absorption is attributable to sample vibration reflecting an extremely high flow resistivity of the mesoporous structure.