Rheological properties of emulsions formed by polymer solutions and modified by nanoparticles

Rheological properties of concentrated oil-in-water emulsions containing dissolving polymers in both phases, partially playing a role of surfactants, were studied. Additionally, nanoparticles were added to the aqueous phase, and they had an influence on rheological behavior and emulsion stability. The main peculiarity of the objects is the superposition of viscoelastic properties related to the presence of polymers and to interface interactions. Emulsion viscoelasticity were characterized by three separate relaxation modes with very different relaxation times. They reflect relaxation processes of polymeric origin inside both phases, which are dilute polymer solutions, and elasticity of interface layers. Presence of nanoparticles strongly affects the rheological properties leading to the increase in the apparent viscosity, elastic modulus, and yield stress of emulsions.