Surfactant Stabilized Oil-in-Water Nanoemulsion: Stability, Interfacial Tension, and Rheology Study for Enhanced Oil Recovery Application

Nanoemulsions are kinetically stable biphasic dispersion of two immiscible liquids typically stabilized by an emulsifier with droplet sizes in the range of 10–200 nm. Present work deals with the formulation and characterization of stable oil-in-water nanoemulsions using nonionic surfactant (Tween 40) and light mineral oil for their application in enhanced oil recovery. The stability study of the nanoemulsions formed by high energy and low energy method was accomplished by bottle testing method. The emulsions were characterized in terms of droplet size, morphology and inner structure, surface charge, interfacial tension, and rheology. Droplet sizes of 18–31 nm obtained by dynamic light scattering analysis and surface charge values above −35 mV obtained by ζ potential measurement prove the higher kinetic stability of the formed emulsions. Cryo-TEM micrographs reveal the surface morphology and inner structure of nanoemulsions. A miscibility test was performed to determine the dissolving ability of the nanoem...