Droplet size distribution of oil-in-water pickering emulsions stabilized by cellulose nanofibers using restricted diffusion NMR

In this study, droplet size distributions (DSDs) of oil-in-water Pickering emulsions stabilized by cellulose nanofibers (CNFs) estimated from NMR diffusion measurements in conjunction with cogent mathematical modelling based on the Gaussian phase distribution (GPD) approximation for diffusion in a sphere. The effects of oil types and Pickering stabilizer loadings on DSDs were investigated by using different n-alkanes (octane to hexadecane) and CNF concentrations (0.5-1%). The NMR diffusion data of the dispersed oil were well-described by the GPD model with a monomodal log-normal distribution. Pickering emulsions composed of higher n-alkane carbon number and/or CNF concentration were found to have smaller median radii, RMedian, and these RMedian estimates were in good agreement with laser scattering data. The volume-based RMedian against the CNF concentrations or the number of hydrocarbon n-alkanes exhibited an approximate exponential relationship.