Cation enhanced hydrophilic character of textured alginate gel beads

The hydrophilic character of modified polysaccharides has been studied by means of water adsorption at 303 and 323 K. Modification of the initial material results from either the introduction of cationic species in the organic framework of polysaccharides (Ca or Co, up to 15%, w/w) or the drying stage of the final materials leading to aerogels or xerogels. The hydrophilic character of the final materials has been discussed in terms of water adsorption or absorption capacities. A strong enhancement of this property is evidenced when using aerogel textured materials as compared to xerogels regardless of the nature of the cation introduced in the organic framework. Water absorption capacities are also further strongly enhanced when cobalt is used as complexing species. This difference between calcium and cobalt species towards adsorption has been discussed in terms of hydration spheres, whereas water absorption has been interpreted in terms of cationic-mediated organic framework expansion.