Effect of hydrophobic and hydrophilic groups on physicochemical properties of nonionic gemini surfactants for oilfield application
摘要
In recent years, the continuous surge in developing stable surfactants capable of withstanding harsh reservoir conditions has attracted considerable attention for enhanced oil recovery (EOR) applications. In this context, four new nonionic gemini surfactants (NGS-1, NGS-2, NGS-3, and NGS-4) with different tail groups and different ethoxy units were synthesized. The surfactants were prepared using various alkyl ethoxylated alcohols as tails and α,α′-dibromo-p-xylene as the spacer, and their structures were confirmed by NMR and FTIR. The thermal stability was evaluated using a thermal gravimetric analyzer (TGA), while solubility tests were performed in deionized water and saline water. Furthermore, surface properties, such as critical micelle concentration (CMC), surface tension at CMC (γCMC), maximum surface excess (Гmax), and minimum area per molecule (Amin), Gibbs free energy of micellization (