2.6.4. Confocal Raman spectroscopy
Confocal Raman images were obtained using an Alpha300 Confocal Raman Microscope (WITec, Germany). Firstly, the pure materials were scanned as standards to obtain the standard spectra and characteristic wavenumber peaks. The coated sample was then scanned and the wavenumbers of the standard characteristic peaks were chosen for the instrument to assemble the image. If the active was detected on the MCC, accordingly a region of bright colour would appear on the image. In addition, surface point analysis was also investigated. The point of selection would either be an uncoated region (i.e. MCC) or a coated region (i.e. the active). If the coating was thin then the scan obtained detected characteristic wavenumber peaks of both the active and MCC in the spectra.