Morphology and porosity of pure and magnetite nanoparticles decorated porous cellulose nanocrystal cryogel monoliths

The investigation of porosity and porous materials have been of great interest to the medical field. Cellulose nanocrystals (CNC) are an attractive biocompatible natural material currently under development for use in tissue engineering. Herein, we probe the fabrication of carboxylated CNC-based cryogel scaffolds using the freeze-casting technique. We also employed a combination of characterization techniques to probe scaffold porosity, including scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), and dynamic vapor sorption (DVS). Our findings showed that macropore morphologies of the CNC-based cryogel scaffolds depend on the conditions under which water freezing takes place. The SAXS data fitted using the mass fractal model and power law suggest that the CNCs aggregated to form well-defined walls in the range of 96.7 nm – 27.3 nm for all samples, while the incorporation of nanoparticles disrupted this compactness in the range of 27.3 – 4.8 nm. The nanoparticles also showed a direct influence on water uptake of the cryogel scaffolds by reducing water sorption mesopores with a radius of 5 – 6 nm, as shown by the DVS technique.