Table 1.
Assignment, vibrational modes, and positions (wave number in cm−1) of FTIR bands in the spectra of PGA, AgNpPGA (0.1), and AgNpPGA (0.4)
| Assignment | Vibrational modes | Band position (cm−1) | Appearance | ||
|---|---|---|---|---|---|
| PGA | AgNpPGA (0.1) | AgNpPGA (0.4) | |||
| O–H | Stretching | 3380 | 3410 | 3400 | Broad and strong |
| Amide I | Associated amides | 1650 | 1600 | 1630 | Medium to strong |
| C=O | Symmetric | 1400 | 1400 | 1390 | Medium to strong |
| N–H | (δ) In-plane bending or scissoring | 1300 | 1300 | 1300 | Weak to medium |
| C–N | Stretching | 1050 | 1080 | 1150 | Broad and strong |
| N–H | (ω) Out-of-plane bending or wagging | 760 | 730 | 750 | Weak |
Abbreviations: FTIR, Fourier transform infrared spectroscopy; PGA, poly-α, γ, L-glutamic acid; AgNpPGA, PGA-capped silver nanoparticles.