A Review on Characterizations and Biocompatibility of Functionalized Carbon Nanotubes in Drug Delivery Design
Table 2
The characteristic features of single-walled carbon nanotubes characterized by Raman spectroscopy. Adapted from [66, 67].
Characteristic features
Wavenumbers (cm−1)
Comments
Radial breathing mode (RBM)
100–300
Radial movement of the nanotubes (A1g). When resonating conditions are met, only the Raman spectra of single-walled carbon nanotubes exhibit the RBM peak.
Disorder-induced mode (D-band)
1300–1400
Characteristic to nongraphitic materials due to structural defects in the sp3 carbon atoms containing carbonaceous impurities, which is correlated with the extent of side wall chemical functionalization.
Tangential displacement mode (G-band)
1500–1600
Characteristic of carbon nanotubes, corresponding to a splitting of the E2g stretching mode of graphite, could be superimposed with the G-band of residual graphite.
Second order
2450–2650
First overtone of the D band, often called G′-band. This second order peak is sensitive to the charge exchanged between CNTs and the guest moiety.
