Hierarchically and wood-like cyclodextrin aerogels with enhanced thermal insulation and wide spectrum acoustic absorption

Environmentally friendly aerogels with high performance and multifunction are the next generation of materials with potential applications in thermal insulation and acoustic absorption. It is a great challenge to make a material combining excellent specific strength, good thermal conductivity and low-frequency sound absorption properties, because these properties often have contradictory structural requirements. In this study, we develop a new strategy to resolve the above problem by preparing β-cyclodextrin (β-CD) aerogel with a hierarchical and wood-like porous structure. The unique vertically arranged lamellar structure with the “bridge” between the lamellar not only reduces the solid heat conduction and heat transfer effectively, but also gives β-CD aerogels (BRAA) superior mechanical properties. As a result, the radial thermal conductivity of BRAA is as low as 0.016 W m−1K−1, and the ultra-light aerogel BRAA can withstand nearly 3000 times its own weight. Furthermore, BRAA exhibits outstanding low-frequency sound absorption performance (sound absorption coefficient up to 0.995 at 750 Hz) due to its hierarchical and aligned porous structure. In addition, BRAAs show excellent environmental friendliness since biomass CD as raw materials and have good regenerative ability.