Interactions of sodium polystyrene sulfonate with some imidazolium-based ionic liquids in aqueous solutions

Abstract

In this work, the effect of temperature and concentration of imidazolium-based ionic liquids ([BMIm]Br, [HMIm]Br, and [OMIm]Br) on the intrinsic viscosity of sodium polystyrene sulfonate (NaPSS) was investigated, and the excellent conformance of obtained data to Wolf's equation was observed. Moreover, addition of ionic liquids screened the electrostatic repulsion between charges along the backbone of the polyelectrolyte chain, leading to the declined intrinsic viscosity of NaPSS by increasing concentration of ionic liquids. The results also revealed that the intrinsic viscosity of NaPSS in the presence of ionic liquids is in the order of [BMIm]Br>[HMIm]Br>[OMIm]Br. The UV–vis spectra of NaPSS show that the absorption intensity of NaPSS was decreased with the addition of ionic liquids. Because of the decreased the expansion factor of polymer chains in the presence of ionic liquids, the value of electric multipole moment showed a consequent decrease. As a result, the absorption intensity of NaPSS was decreased with the addition of ionic liquids.