STABILIZING BOTH OIL DROPLETS AND TITANIUM DIOXIDE NANOPARTICLES IN AQUEOUS DISPERSION WITH NANOFIBRILLATED CELLULOSE

Nanocellulose is a efficient stabilizer for several colloidal systems,
including emulsions and inorganic nanoparticles, replacing surfactants,
polymers, and other additives, therefore providing more minimalist and
eco-friendly formulations. However, could this ability be extended to more
complex mixtures? This work aimed to answer this question, investigating
how nanocellulose could stabilize oil droplets and metal oxide
nanoparticles present in the same colloidal system (Figure 1). For this
puprose, we have examined either cationic or anionic nanobrillated
celluloses to stabilize both titanium dioxide nanoparticles and oil droplets.
The resulting suspensions hold their macroscopic stability for up to 2
months, regardless of pH or NFC surface charge. Cryo-TEM images
revealed a complex network formation involving nanofibers, oil droplets
and TiO2NPs, which agrees with the high viscosity values and gel-like
behavior found in rheology measurements. We propose that the formation
of this network is responsible for the simultaneous stabilization of oil
droplets and TiO2NPs, and that this may be used as a formulation tool for
other complex systems