*2.2.2. Fourier Transform Infra-Red (FT-IR) spectroscopy*

FT-IR spectra of dry AX1 and AX2 were recorded on a Nicolet FT-IR spectrometer (Nicolet Instrument Corp. Madison, WI, US). The samples were pressed into KBr pellets (2 mg/200 mg KBr). A blank KBr disk was used as background. The spectra were measured in absorbance mode from 400–4000 cm-1 resolution [16].
