*2.7. Fourier-Transform Infrared Spectroscopy (FTIR) Analysis*

– −1 −1 The chemical structure of the cellulose nanofiber was analyzed by FTIR analysis. A FTIR-ATR Perkin-Elmer Spectrum Two was used to collect 20 infrared spectra in the range of 450–4000 cm−<sup>1</sup> with a resolution of 4 cm−<sup>1</sup> . The analysis was performed on a CNF film prepared by hot-drying the cellulose nanofiber suspension.
