Chitosan–montmorillonite bio-based aerogel hybrid microspheres

Natural and biocompatible porous hybrid microspheres have been prepared by gelation of an intercalated “chitosan–montmorillonite” solution followed by drying with super-critical CO2. This drying method allowed generating an open framework of fibrillar chitosan–montmorillonite in which chitosan is petrified by the clay platelets. Monitoring the formation of the dispersed colloidal beads microspheres by wide angle X-ray diffraction analysis evidenced the ingress (in acidic solution) and the egress (in basic solution) of chitosan scaffold within and from the montmorillonite galleries. Consistently with their high surface areas and enhanced accessibility, aerogel microspheres are found to be three times superior to their xerogel version in terms of methylene blue uptake. The presented hybrid materials take advantages from the chemical reactivity of chitosan backbone and the higher stability of clay platelets and pave the way toward positive synergetic effects.

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► New structured hybrid materials are prepared from two natural and available scaffolds (chitosan and clay).
► High surface area materials are generated by CO2 supercritical drying.
► Ingress and egress of the chitosan backbone has been observed during the preparation procedure.