Aerogels prepared using cellulose nanofibers (CNFs) has the renewability, biocompatibility, and biodegradability of cellulose, while also having other advantages such as low density, high porosity, and a large specific surface area.

In addition to possessing the inherent properties of a polymer obtained from bio-based resources, nanocellulose can be combined with other functional component to gain certain added value.

The stable nature of colloidal systems has tremendous potential to satisfy the manufacturing requirements of composite structures, unobtainable using traditional methods. This enables materials delivery and assembly across the multiple scales required to achieve optimized properties.

This work includes a practical strategy to manufacture highly homogeneous composites materials in aerogel format from mixtures of metal oxides nanoparticles (MONPs) and CNFs obtained from biomass valorisation[1,2]. Two semiconductor-based nanoparticles such as TiO₂ or CuO were used for the prepared formulations.

The emphasis was specially placed on the mixtures handling in liquid media and the functionalization of materials surfaces. To improve the dispersion/stabilization in liquid media and to favour the electrostatic interaction between MONPs and CNFs, the surface of inorganic material was previously modified by adsorbing different amounts of a cationic polyelectrolyte (polyethylenimine, PEI). The MONPs-PEI suspension was added to a CNF dispersion at different percentages on CNF dry weight causing a three-dimensional and attractive network between both components.

 The photocatalytic and antimicrobial activities of the resulting aerogels were finally analysed.

References

[1] Gonzalez, Z. et al. Cellulose 2020, 27 (13), 7543–7559.

[2] Carrasco, S. et al. ACS Sustainable Chemistry & Engineering 2023, Accepted