Structural and acoustic properties of transparent chitosan aerogel

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 similar to 45 to similar 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. (C) 2019 Elsevier B.V. All rights reserved.