Facile construction of gemini-like surfactants at the interface and their effects on the interfacial tension of a water/model oil system

Abstract

The application of supramolecular chemistry may be a promising and convenient approach to construct desired surfactants via noncovalent interactions in various fields, including chemical enhanced oil recovery (EOR). Gemini-like surfactants were fabricated by combining sodium dodecyl benzene sulfonate (SDBS) and butane-1,4-bis(methylimidazolium bromide) (BBMB) at the interface and evaluated for their ability to reduce the interfacial tension (IFT) between water and a model oil (toluene and n-decane, v/v = 1 : 1). The SDBS/BBMB molar ratio at the interface, but not in the bulk phase, was the crucial factor in the construction of gemini-like surfactants and the reduced level of IFT. Based on the synergistic effect between electrostatic attraction and other intermolecular or intramolecular interactions (π–π stacking and hydrophobic interaction), the formation mechanism of gemini-like surfactants was proposed. The effects of temperature and salinity on the IFT were systematically investigated. Moreover, the (SDBS)₂/BBMB gemini-like surfactant system showed the desired ability to reduce the IFT of water/crude oil and a great improvement in crude oil recovery.