Formation of supramolecular structure in alginate/chitosan aerogel materials during sol-gel synthesis

Alginate/chitosan (AlgNa/Cht) aerogels and carbogels with a developed micro-mesoporous structure were produced. For the first time, the classical scheme, including the sol-gel process and supercritical fluid drying, was applied to obtain the two-component AlgNa/Cht aerogel materials with predicted properties. The obtained aerogels and carbogels have a specific surface area up to 399 m2g−1 and 549 m2g−1, respectively, and tubular pore structure. The morphological characteristics of the samples were investigated by atomic force microscopy and by scanning electron microscopy. It was shown that carbogels have narrow globular particle size distribution (35–45 nm). The synthesis conditions (critical concentration and syneresis region) are established under which the coagulum is formed in the form of an interpolyelectrolyte complex. The calcium carbonate impregnation into AlgNa/Cht system leads to an almost instantaneous formation of a hydrogel. Moreover, it allows changing material structure due to the additional nodes of the fluctuation mesh of engagement, which leads to an increase in the sizes of associative structural formations of aerogel materials, its strength, and high dimensional stability. The use of the template allowed to increase the specific surface area and the mesopores volume in the of the carbogels in 1.5–2 times. Due to such structure, the 1 g of aerogel material retains 20–35 g of water while maintaining shape. The shape of the monolith in the carbogel is maintained. Obtained AlgNa/Cht aerogels are of medical and biological interest.