Aerogels of polysaccharides as bio-based templates

Abstract

Aerogels of polysaccharides can be used as bio-based template materials for many applications including separation techniques, catalysis, tissue engineering and drug delivery vehicles because of their abundance in renewable natural source, ease of production, bio-compatibility and biodegradability [1-3]. Aerogels of polysaccharides such as cellulose and carrageenan were successfully synthesized in three consecutive steps: a) preparation of hydrogels; b) solvent exchange; and c) drying the organogels under supercritical condition (supercritical fluid is carbon dioxide). Their properties were investigated by envelope density analyzer, scanning electron microscopy and nitrogen adsorption-desorption analysis. The density of carrageenan aerogel was about two times higher than cellulose aerogel because of the difference in shrinkage behavior of polysaccharides under supercritical condition. The macro- and mesoporous fibrillar structure was observed with a fibre thickness of about 10-20 nm. The specific surface area of aerogels showed almost constant value for cellulose and carrageenan. These aerogels were used as bio-based template to prepare composite materials.