Functionalization of γ-Alumina and Magnesia Nanoparticles with a Fluorocarbon Surfactant to Promote Ultra-Gas-Wet Surfaces: Experimental and Theoretical Approach

A promising alternative to improve the ultra-gas-wet alteration process by the addition of nanoparticles was developed. This study is focused on studying the functionalization process of nanoparticles of γ-alumina (γ-Al₂O₃) and magnesia (MgO) using a commercial fluorocarbon surfactant (SYLNYL-FSJ), from an experimental and theoretical approach. Different fluorocarbon surfactant concentrations were used in the functionalization process of the nanoparticles, and the materials obtained were characterized by Fourier-transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). The experimental setup of the interaction between the surfactant and nanoparticles was reproduced by molecular simulations in order to obtain physical insights into the adsorption process. Experimental results show a suitable functionalization for both nanoparticles with the fluorocarbon surfactant. The γ-Al₂O₃ nanoparticles showed better behavior based on the obtained nonfrictional conditions, which lead the water and n-decane droplets to slide on the rock surface coated with the functionalized nanoparticles. The experimental contact angles on the functionalized γ-Al₂O₃ nanoparticles were reproduced by molecular dynamics simulations. From the interaction energies' evaluation, it was also determined that alumina nanoparticles could reduce the adhesive energy to 0.01 kcal mol^-1, regarding magnesia nanoparticles. Also, a significant difference was obtained for the surfactant-liquid interactions between the two nanoparticles evaluated, with changes of 17% for surfactant-water interactions and 28% for the surfactant-n-decane. The obtained results explain the pronounced increase for the contact angles of n-decane on the functionalized γ-Al₂O₃ nanoparticles.