The present study is conducted in order to investigate the role of counter anion, temperature and alkyl chain length on the adsorption of four long-chain imidazolium-based ILs, at the interface of n-butyl acetate + water system as recommended system for investigations. The used ILs act as excellent surfactants and the experimental data were satisfactorily reproduced by the Szyszkowski adsorption equation for concentrations less than CMC; therefore the Langmuir maximum interface excess and equilibrium adsorption constant were obtained at different temperatures for each IL.
