Effect of anionic polyelectrolyte sodium carboxymethylcellulose on the aggregation behavior of surface active ionic liquids in aqueous solution

Abstract

In the present study, we reported the effect of sodium carboxymethylcellulose (NaCMC), an anionic polyelectrolyte on the aggregation morphological variations of cationic surface active ionic liquids (SAILs) for example 1-tetradecyl-3-methylimidazolium bromide [C14mim][Br] and 1-hexadecyl-3-methylimidazolium bromide [C16mim][Br]. The measurements have been carried out by utilizing techniques such as surface tension, conductance, fluorescence, dynamic light scattering and rheology. The results obtained from surface tension measurements shows that surface properties and aggregation process of SAILs have been extensively influenced by the addition of polyelectrolyte. So, the humps have been observed in the tensiogram corresponding to different states of interaction. The various surface parameters such as surface excess concentration (Γmax), surface pressure at the interface (Πcmc), minimum area occupied by single SAIL molecule at air-solvent interface (Amin), adsorption efficiency (pC20) and surface tension at critical micelle concentration (cmc) (γcmc) have been calculated from surface tension measurements. The results obtained from tensiometric and conductometric measurements have been further confirmed by fluorescence, dynamic light scattering and rheology results. It has been observed that the cmc values of both the SAIL systems increases with increasing concentration of NaCMC.