2.2.4. FTIR Spectroscopy

The IR absorption spectrum of uncoated NCC was generated using a 100 Spectrum FTIR ATR spectrophotometer (PerkinElmer, Beaconsfield, UK) and analyzed using Peak® version 4.00 spectroscopy software (Operant LLC, Burke, VA, USA). Approximately 5 mg of powder was placed onto a diamond crystal and analyzed over the wavenumber range 4000–650 cm<sup>−</sup><sup>1</sup> at a rate of 4 cm<sup>−</sup><sup>1</sup> (replicates *n* = 5) and the spectrum for the micro co-crystals was used for reference purposes.
