Supercritically-Dried Alginate Aerogels Retain the Fibrillar Structure of the Hydrogels

SAXS patterns of a Ca-alginate hydrogel and of the derived alcogel and aerogel have been recorded. All patterns correspond to disordered arrays of rod-like fibrils. The calculated size of the fibrils of the aerogel, 8 nm, is in good agreement with the results of scanning electron microscopy and N₂ adsorption. The results suggest that ethanol exchange and CO₂ supercritical drying do not affect the spatial organisation of the secondary structures of the gel and that characterisations of the aerogel can provide information on the organisation of the parent hydrogel.