## 3 Results and Discussion
### Molecular and Structural Modifications Identified by FTIR Spectroscopy
#### 3.3.3 Lipid Degradation and C-H Stretching (3000 and 2850 cm\({}^{-1}\) Region)  
The absorption bands at 2923 cm\({}^{-1}\) and 2858 cm\({}^{-1}\), associated with asymmetric and symmetric C-H stretching in lipids, were diminished after both treatments, indicating partial degradation of the lipid layer. The effect was most significant for coily hair (Sample 4) treated with PAW-N, which aligns with SEM evidence of severe cuticle erosion. This degradation is reflected in the increase in oxygen content and decrease in carbon percentage observed by EDS. For Sample 4, PAW-N treatment resulted in oxygen levels of 21.4% compared to 22.0% in the control, while carbon content increased slightly (from 72.6% to 72.8%), possibly due to lipid removal and exposure of underlying protein. In contrast, PAW-P treatment preserved the lipid structure more effectively, as indicated by more stable carbon and oxygen values (C: 77.4%, O: 18.7%) and less reduction in C-H bands. 3.3.4. Impact on Protein Backbone Via Amide I & II Bands (1650 and 1550 cm\({}^{-1}\) Region)  
The Amide I (1645 cm\({}^{-1}\)) and Amide II (1538 cm\({}^{-1}\)) bands--key markers of the keratin backbone--exhibited reduced intensity after PAW treatments, denoting protein unfolding or partial denaturation. The reduction was significantly more severe under PAW-N, particularly in wavy (Sample 1) and coily (Sample 4) hair, suggesting destabilization of protein secondary structures. These findings are consistent with the EDS-derived elemental profiles, which show a notable decrease in sulfur content in Sample 1 (from 3.5% to 2.8%) and Sample 4 (from 5.0% to 5.2%) after PAW-N treatment, indicating disulfide bond cleavage and structural weakening. In contrast, PAW-P induced milder alterations in Amide bands and maintained relatively stable elemental compositions, supporting its gentler impact on protein integrity. 3.3.5. Evidence of Lipid Oxidation (1734 cm\({}^{-1}\) Region)  
The C=O stretching band near 1734 cm\({}^{-1}\), typically attributed to lipid oxidation products, became more evident after PAW-N exposure--particularly in Sample 4 (coily hair). This spectral change suggests that PAW-N promoted degradation of the lipid layer, likely through oxidative cleavage of ester bonds. This interpretation is consistent with the EDS data (Table 3): after PAW-N treatment, Sample 4 showed a decrease in oxygen content (from 22.0% to 21.4%) but a notable increase in carbon (from 72.6% to 77.4%). This relative carbon enrichment may reflect the loss of polar oxygenated species from degraded lipids, or rearrangement of the surface composition due to erosion of the oxidized layer. In contrast, PAW-P led to a smaller increase in the 1734 cm\({}^{-1}\) band, and the corresponding EDS data for Sample 4 showed less variation in both oxygen (18.7%) and carbon (77.4%), suggesting milder lipid oxidation and better structural preservation. 3.3.6. Overall Structural Disruption in the Fingerprint Region (1500-500 cm\({}^{-1}\))  
The fingerprint region of the FTIR spectra revealed more disordered signals and broadened peaks after PAW-N treatment, indicating substantial structural changes in the protein and lipid components of hair. These effects were particularly evident in Samples 1 and 4, both of which also showed visible cuticle degradation under SEM. EDS results corroborate this observation: Sample 1 showed a significant increase in carbon content after PAW-N (from 74.0% to 87.0%) and a decrease in oxygen (from 21.7% to 9.4%), which may suggest the removal of oxidized functional groups and possible leaching of polar residues. The sulfur content also dropped (from 3.5% to 2.8%), consistent with the loss of disulfide bonds. Similar trends were observed for Sample 2. These changes reinforce the FTIR evidence of severe molecular disruption. For PAW-P, the fingerprint region remained more defined, indicating less extensive damage.