Bioinspired assembly of layered double hydroxide/carboxymethyl chitosan bionanocomposite hydrogel films

Abstract

Carboxymethyl chitosan (CMC) intercalated Mg–Al layered double hydroxides (C-LDHs) with high dispersion in the CMC matrix were successfully synthesised by a one-pot method using a facile biopolymer-assisted approach in the presence of CMC under hydrothermal conditions. Highly oriented, flexible and glossy self-supporting C-LDH/CMC bionanocomposite hydrogel films with good mechanical properties were bioinspired assembled using C-LDH nanoplatelets and CMC molecules as building blocks via the solvent evaporation process. The results of X-ray diffraction and scanning electron microscopy showed that the bionanocomposite film had a bioinspired layered structure. The film thickness and equilibrium swelling ratio of the C-LDH/CMC bionanocomposite film could be changed by adjusting the C-LDH mass content. The film with a high C-LDH mass content had high swelling stability, which may be attributed to the LDH nanoplatelets that could act as crosslinkers to reinforce the bionanocomposite film structure. Lysozyme could be immobilised in the C-LDH/CMC bionanocomposite hydrogel film through the electrostatic interaction.