Table 3.

FTIR band positions of chitosan–TiO₂ composite.

Band Position	Assignment	Ref.
3450	OH bond of chitosan; it could exist an electrostatic interaction of N–H–O–Ti	[15,16]
3350	Combined peaks of the NH2 and OH group stretching vibrations	[69]
3300	Strong interaction between NH2 and OH with TiO2	[40,69]
2934	Asymmetrical stretching vibration of the C–H in CH2 and CH3 groups	[55,70]
2923–2872	C–H asymmetric and symmetric vibrations, TiO2–OH functional group	[8]
1735–1733	O–C–NH2 indicated the presence of titanates in the composite	[71]
1637–1715	N–H scissoring from the primary amine, it could exist an interaction of Ti4+ with –NH2	[50,68,72,73]
1577–1589	Angular deformation of N–H bonds	[51,74]
1538	Secondary amide (amide II), CH2 bending	[60]
1528–1534	C–N and C–N–H bending mode	[5,68]
1421	C–N axial deformation (amine group); C–O stretching (amide I)	[45,70]
1370–1420	C–O–C stretching bands, N = O vibrations, –NH deformation, CH3 group	[15,70,73,74]
1287	Ti–OH and Ti–O bonds	[15,70]
1029–1152	C–N bending vibrations and asymmetrical stretching vibrations of C–O–C glycosidic bonds, Ti–O–C bending mode, Ti–OH bond	[10,15,16,17,70,74,75]
600–900	Ti–O–Ti bond, asymmetric stretching mode of Ti–O, immobilization of TiO2 onto the CS matrix	[5,15,16,70,74]
385–600	Ti–O–C, it could exist an interaction of Ti Lewis site with -NH2 groups of chitosan chain	[42,50,69]