Chitosan bionanocomposites prepared in the self-organized regime
Abstract Bionanocomposites in the self-organized regime are prepared when chitosan is gradually charged in the course of progressive change of pH by hydrolyzing D-glucono-δ-lactone in solutions of nanoparticles bearing negative charges on their surface. This novel approach is applicable to the formation of monolithic hydrogels and films. Here bionanocomposites of chitosan with clay nanoparticles of saponite and sepiolite having various geometry and with oxidized multiwall carbon nanotubes are considered. Structural organization of hydrogels and films is studied by scanning and transmission electron microscopy as well as small angle X-ray scattering. Jellification is caused by generation of three-dimensional network from fibrils, whereas films have pronounced stratified layer (nacre-like) structure from stacked nanoparticles and aligned chitosan macromolecules. Special attention is paid to mechanical properties of films that are improved drastically with introducing nanoparticles.