Nicolet in10 ftir

FTIR spectroscopy was used for the vibrational characterization of all the PILs on the basis of interactions between the methanesulfonic acid and the different nitrogen-containing bases. The full range of infrared, typically used to characterize the organic molecules, was covered during the analysis of the prepared samples. A Perkin Elmer FTIR spectrophotometer (Spectrum 100, Perkin Elmer Cetus Instrument, Norwalk, CT, USA) was used to obtain the FTIR spectra of the above samples on a KBr cell at room temperature in the 4000–400 cm⁻¹ frequency region. The FTIR spectra of the neat PBI and the composite membrane samples were obtained in ATR mode at room temperature using a Nicolet iN10 FTIR (Thermo Scientific, Winsford, UK) with a germanium microtip accessory in the 4000–650 cm⁻¹ frequency region.

FTIR analyses were conducted using frozen untreated and FCLAPs‐treated samples, and performed by a spectrophotometer (Nicolet iN10 FT‐IR, Thermo Fisher Scientific, Waltham, MA, USA) with the absorption spectra recorded within the range of 4000–400 cm⁻¹. Background obtained from the pure potassium bromide (KBr) disc was automatically subtracted.