RAIRS Investigations on Films of the Ionic Liquid [EMIM]Tf2N

The reflection-absorption infrared (RAIRS) spectra of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM]Tf2N) are presented for liquid as well as for amorphous and crystalline solid films. The liquid and amorphous films show rather similar spectra, indicating that the film structure is similar in both cases. On the other hand, these spectra differ considerably from those of crystalline films, indicating that the film structure is different for liquid and crystalline films. There are however indications that in all of the studied phases, including the crystalline state, the cation interaction with the SO2 groups of the anion dominates.