Table 2 Assignment of FTIR spectra for the three synthesized polymers

P(TRI-co-TER)

1699

C=O stretching for carboxylic acid [24]

1448

N–H and C–H in plain bending, C–C stretching for normal vibration of pyrrole ring [22]

1228

C–N stretching at benzene ring [27]

1110

\({\text{NH}}^{ + }\) stretching between quinones and benzene ring [27]

698

C–H out of plane bending at aromatic ring [24]

P(TRI-co-DISULF)

3377

N–H stretching for normal vibration of pyrrole ring [22]

3066

C–H stretching at aromatic ring [23]

1624

C=N stretching in quinones ring [27]

1541

C=C stretching in quinones ring [25]

1487

N–H and C–H in plain bending, C–C stretching [28]

1371, 1325

S=O stretching [24]

752

C–H, and N–H out of plain bending [28]

678

C–H, and N–H out of plain bending [28]

PINDOLE

3385

N–H stretching for normal vibration of pyrrole ring [22]

3066

C–H stretching at aromatic ring [23]

1701

C=O stretching for carboxylic acid [24]

1624

C=N stretching in quinones ring [25]

1541

C=C stretching in quinones ring [25]

1487

N–H and C–H in plain bending, C–C stretching [28]

1382

N–H and C–H in plain bending, C–C stretching [28]

1197

C–H in plain bending [22]

1101

\({\text{NH}}^{ + }\) stretching between quinones and benzene ring [27]

1045

C–O–C stretching [24]

750

C–H, and N–H out of plain bending [28]

678

C–H, and N–H out of plain bending [28]

578

C–H, and N–H out of plain bending [28]