Experimental Investigation of PEG 6000/Tween 40/SiO2 NPs Stabilized Nanoemulsion Properties: A Versatile Oil Recovery Approach

The article presents a comprehensive oil recovery approach through experimental investigations and mechanistic descriptions of formulated nanoemulsion systems stabilized by {PEG 6000 (an amphiphilic polymer), Tween 40 (a non-ionic surfactant) and silica nanoparticles (SiO 2 NPs)}. Initially, polymers were screened for emulsion preparation depending on their surface active properties and solubilization parameters. Oil droplets of nano-size (<500 nm) were measured by dynamic light scattering (DLS) in emulsion phase. The prolonged kinetic stabilities of nanoemulsions were inspected by zeta (ζ) potential and phase behavior studies. The mechanical barrier (steric hindrance + electrostatic repulsion) is strengthened at oil-aqueous interface by NPs inclusion occasioning augmented emulsion stability. Surface tension measurements quantified the air-emulsion interfacial behavior and lowest value of 6.42 mN/m at 343 K signifies the improved adsorption of polymer, surfactant and NPs at the interface in polymer-surfactant-NPs (PSN) nanoemulsion system. Viscosity analysis at varying temperatures concludes the pseudo-plastic behavior through fitting of flow parameters by Power law model. The hydrophobic connection of viscosification of nanoemulsion by formation of macromolecular and supramolecular structures is described mechanistically. The miscibility test infers the improved emulsification of crude oil by PSN nanoemulsion system with synergistic interactions among polymer, surfactant and nanoparticles. The core flood test yielded an additional oil recovery of 27.82% of original oil in place (OOIP) by PSN nanoemulsion, after conventional water flooding. • Experimental and mechanistic investigation of nanoemulsions for oil recovery • Enhanced properties of PEG 6000-Tween 40-SiO 2 NPs stabilized nanoemulsions • Viscosity enhancement by macromolecular and supramolecular network structures • Shear thinning and shear thickening nature was displayed by nanoemulsions. • Improved miscibility properties of PSN nanoemulsion system with crude oil