2.3.3. FTIR Spectroscopy

The IR absorption spectrum of the OPT-NCC was generated using a Model 100 Spectrum FTIR ATR Spectrophotometer (PerkinElmer) and analyzed using version 4.00 Peak ® Spectroscopy software (Operant LLC, Burke, VA, USA). Approximately 5 mg 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> in replicate (*n* = 5) and the spectrum for the uncoated nano co-crystals was used for reference purposes.
