Figure 4. Investigation of residual PEG (a) and significant water content using Raman spectroscopy ((b) and (c)).
None of the fibres demonstrated the characteristic PEG peak at a wavenumber of around 2900 cm−1 [31]. There were also not significant peaks present attributable to the δ or ν modes of water absorption at 1640 or 3280 cm−1 [32].