## 3 Results and Discussion
### Mechanisms of Action of PAW-N and PAW-P on Different Hair Types
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Feature/Effect** & **PAW-N (Nitrate-Rich)** & **PAW-P (Pervoide-Rich)** &
\begin{tabular}{c} **Hair Type** \\ **Susceptibility** \\ \end{tabular} \\ \hline
**Chemical Composition** & \begin{tabular}{c} High \(\text{NO}_{3}\)\({}^{-}\) (\(\sim\)500 mg/L), \\ low pH (2.15), high ionic \\ strength (6244 \(\upmu\)S/cm) \\ Strong, driven by nitrate \\ species and high \\ conductivity \\ Extensive cleavage in wavy \\ and one straight sample (1 \\ Cleavage (1040 cm\({}^{-1}\)) \\ \end{tabular} & \begin{tabular}{c} High \(\text{H}_{2}\text{O}_{2}\) (\textgreater{}25 mg/L), \\ low pH (2.15), high ionic \\ strength (6244 \(\upmu\)S/cm) \\ Strong, driven by nitrate \\ species and high \\ conductivity \\ Extensive cleavage in wavy \\ and one straight sample (1 \\ and 2); retention or \\ reformation in \\ samples 3 and 4 \\ Lipid Layer Degradation \\ (2925–2850 cm\({}^{-1}\)) \\ \end{tabular} & \
\begin{tabular}{c} High \(\text{H}_{2}\text{O}_{2}\) (\textgreater{}25 mg/L), \\ moderate pH (2.54), lower \\ ionic strength (6244 \(\upmu\)S/cm) \\ Strong, driven by nitrate \\ species and high \\ conductivity \\ Extensive cleavage in wavy \\ and one straight sample (1 \\ and 2); retention or \\ reformation in \\ samples 3 and 4 \\ Significant peroxidation, \\ especially in coily and \\ \end{tabular} &
\begin{tabular}{c} High \(\text{H}_{2}\text{O}_{2}\) (\textgreater{}25 mg/L), \\ moderate pH (2.54), lower \\ ionic strength (Type 1) \\ more resistant \\ Coily and wavy hair show \\ greater oxidative reactivity \\ under PAW-N \\ Higher susceptibility in \\ porous types under PAW-N \\ \end{tabular} \\
**Disulfide Bond** & \
\begin{tabular}{c} Moderate and uniform \\ increase in cysteic acid \\ across all types \\ \end{tabular} &
\begin{tabular}{c} Higher susceptibility in \\ porous types under PAW-N \\ Coily and wavy hair show \\ greater lipid loss under \\ PAW-N \\ \end{tabular} \\
**Cleavage (1040 cm\({}^{-1}\))** & \
\begin{tabular}{c} High reduction; keratin \\ structure retained \\ \end{tabular} &
\begin{tabular}{c} More prominent in porous \\ hair under PAW-N \\ Coily and wavy types \\ exhibit more disruption \\ under PAW-N \\ \end{tabular} \\
**Lipid Layer Degradation** & \begin{tabular}{c} Pronounced fragmentation, \\ lifting, and surface erosion \\ \end{tabular} & \
\begin{tabular}{c} Mild lifting with overall \\ structural preservation \\ \end{tabular} &
\begin{tabular}{c} Coily and wavy \\ exhibit more disruption \\ under PAW-N \\ \end{tabular} \\
**Moisture Loss (3400–3300** \\ **cm\({}^{-1}\))** & \begin{tabular}{c} Marked dehydration and \\ hydrogen bond disruption \\ \end{tabular} & \
\begin{tabular}{c} Partial water loss; \\ hydrogen bonding \\ partially preserved \\ \end{tabular} &
\begin{tabular}{c} Greater moisture loss in \\ porous hair under PAW-N \\ \end{tabular} \\
**Lipid Oxidation (1730** \\ **cm\({}^{-1}\))** & \begin{tabular}{c} Prominent oxidation \\ products in coily and \\ wavy hair \\ Oxidative cleavage \\ followed by partial \\ reorganization (esp. in \\ dense fibers) \\ \end{tabular} & \
\begin{tabular}{c} Limited oxidation; minor \\ increase in lipid \\ degradation bands \\ \end{tabular} &
\begin{tabular}{c} Lipid oxidation is mainly \\ significant under PAW-N \\ \end{tabular} \\
**Structural Rearrangement** & \
\begin{tabular}{c} Controlled oxidation \\ promotes structural \\ stabilization \\ \end{tabular} &
\begin{tabular}{c} Partial reformation in coily \\ hair under PAW-P \\ \end{tabular} \\
**Overall Hair Integrity** & \begin{tabular}{c} Compromised: increased \\ porosity, cuticle damage, \\ and protein loss \\ \end{tabular} & \
\begin{tabular}{c} Preserved: surface-level \\ oxidation with minimal \\ core damage \\ \end{tabular} &
\begin{tabular}{c} PAW-P more appropriate \\ for sensitive hair types \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}