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.