Investigation on the Interactions of Poly(ethylene oxide) and Ionic Liquid 1-Butyl-3-methyl-imidazolium Bromide by Viscosity and Spectroscopy

In this research, the solution of poly(ethylene oxide) in binary mixtures of water and ionic liquid, 1-butyl-3-methyl imidazolium bromide, were studied via spectroscopic and viscometric at the temperature range of 288.15-313.15 K. Also, the effects of ionic liquid, 1-butyl-3-methyl imidazolium bromide, on the thermodynamic parameters of dilute aqueous solutions of poly(ethylene oxide), such as polymer-solvent interaction parameter, theta temperature, the heat of dilution parameter, and the entropy of dilution parameter were investigated. Our data indicate that the thermodynamic quality of water for poly(ethylene oxide) is reduced by the addition of 1-butyl-3-methyl imidazolium bromide and increasing temperature. The flow activation energy was calculated and correlated in terms of polymer concentration. The sign of initial slope of the activation energy versus polymer concentration at zero concentration reveals that thermodynamic quality of IL aqueous solutions is reduced by increasing temperature. The type of interactions between poly(ethylene oxide) and 1-butyl-3-methyl imidazolium bromide was studied by Fourier transform infrared (FT-IR) and UV-vis methods. The existence of hydrogen bonding between the imidazolium cation and the oxygen atom of poly(ethylene oxide) was confirmed by the results of FT-IR and UV-vis spectroscopies.