Exploring the impact of short-chain alcohols and NaCl concentration on the interfacial properties of the water/SDBS surfactant/n-octane system: A molecular insight into the preparation of emulsified systems using MD simulations

MD simulations were carried out to explore the effect of short-chain alcohols and NaCl concentration on the interfacial properties of the water/SDBS surfactant/n-octane system. The optimal formulation conditions for emulsified systems were evaluated at molecular level. The simulations revealed a reduction in the IFT of the systems prepared with the SDBS/n-propanol and SDBS/n-butanol monolayers. These results indicate a strong synergism between these species at the interface. At low NaCl concentrations, the results suggest that the alcohol molecules have a low migration to the n-octane phase remaining in the mixed monolayers stabilizing the emulsified system. At higher NaCl concentrations, the migration of alcohols to the n-octane phase is considerable, producing a rupture of mixed monolayers located at the interface. Energetic analyses suggest that an appropriate lipophilic-hydrophilic balance associated with the molecular interaction between SDBS surfactant and short-chain alcohol is fundamental for the stability of the mixed monolayers at the interface.