Evaluation of the repartition of the particles in Pickering emulsions in relation with their rheological properties

Hypothesis: The distribution of particles in Pickering emulsions can be estimated through a percolation type approach coupled to the evolution of their rheological features with the dispersed phase volume fraction /. Experiments: The rheological behavior of water-in-dodecane Pickering emulsions stabilized with hydrophobic silica nanoparticles is addressed. The emulsions viscosity and elastic modulus are investigated at / varying from 0.1 to 0.75. Various rheological models are adjusted to the experimental data. Findings: The comparison of the elastic modulus evolution of the Pickering emulsions with those of emulsions stabilized with surfactants confirms a major contribution of the particles to the rheological behavior of Pickering emulsions and supports the existence of a three-dimensional network between the droplets. The applied percolation approach allows to quantitively estimate a nanoparticles viscoelastic link between the droplets and opposes the classic vision of interfacial monolayers stabilizing the Pickering emulsions. This network of interconnected particles and droplets contributes significantly to the viscosity as well as the elastic modulus of these emulsions. To our knowledge, the applied percolation-based model is the only one capable of providing a structural explanation while describing the abrupt viscosity and elastic modulus growth of Pickering emulsions across the range of /. (c) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study shows that particles play a significant role in the rheological behavior of Pickering emulsions, supporting the existence of a three-dimensional network between droplets. The applied percolation method can quantitatively estimate a viscoelastic link between particles, which significantly affects the viscosity and elastic modulus of the emulsions, contrary to the traditional view of interfacial monolayers stabilizing Pickering emulsions.