Optical Microscopy and Rheology of TOCNF-Stabilized Emulsions

Certain macroscopically homogeneous samples were subjected to optical microscopy using a DMR-XA microscope from Leica (Wetzlar, Germany). The modes of observation included halogen illumination and polarized light over a dark field. Then, the particle size was analyzed using the open-source software ImageJ (Version 1.53), as described elsewhere [6 (link)], but without using the Fractal Box Count plugin. Instead, the average between the maximum Feret’s diameter and the minimum Feret’s diameter, readily available in the native software package, was taken to indicate the particle size (d). OriginLab’s OriginPro 8.5 was then used to fit the resulting size distributions.
The viscosity of the stable emulsions, including different degrees of oxidation and concentrations of TOCNFs, was measured using a rheometer with concentric cylinder geometry from PCI (Albacete, Spain), model RVI-2. The radii of the spindle and the outer cylinder were 4 mm and 5 mm, respectively. The rheological behavior of the TOCNF-stabilized BW-in-water emulsions was compared with that of the aqueous TOCNF suspensions at the same consistency. The effects of temperature and the influence of the shear rate were studied.