## 4 Results and Discussion
### Influence of Oil Type and Emulsifier Structure on Emulsion Formation  
#### 4.3.1 Effect of Oil Polarity on HIPE Morphology  
The probability of HIPE formation varied significantly depending on the oil type, as different oils contributed differently to the stabilization of the interfacial film based on their polarity and interfacial activity. For the interfacially active amide-based oils (Oil 5-7), seven out of nine emulsifier-oil combinations yielded stable emulsions. All three emulsifiers were able to stabilize Oil 5 effectively, as shown in the porous frameworks depicted in Figure 4(a1-c1). Similarly, the ether-based oils (Oil 8-10), although less active, still formed stable W/O emulsions with AS2 and AS3 emulsifiers (Figure 4(a2-c2)). Conversely, these ether and amide oils failed to form HIPE with AS1, likely due to its limited interfacial activity, and this will be further discussed in the subsequent subsection.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c} \hline \hline
**Water** & **Emulsifier** & **Oil** & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** & **9** & **10** & **11** & **12** & **13** & **14** & **Counts** \\ \hline \multirow{3}{*}{70\%} & AS1 & & & + & & + & & + & & & & & & & & & 3 \\ \cline{2-13}  & AS2 & + & + & + & + & + & + & + & + & + & + & + & & + & & + & 12 \\ \cline{2-13}  & AS3 & + & + & & & + & + & + & + & + & + & + & + & & & & 9 \\ \hline \multicolumn{13}{c}{Counts} & 2 & 3 & 1 & 2 & 3 & 2 & 2 & 2 & 2 & 2 & 1 & 1 & 0 & 1 & \\ \hline \hline \end{tabular}
\end{table}
Table 6: Simulation results for the emulsion model systems at 70% water content. A ‘+’ indicates a positive result (W/O emulsion formation) in at least one of the three repeated runs.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Oil Type** & **Functional Group** & **Simulated IFT Trend** & **Reported IFT Range** & **Ref.** & **Consistency** \\ \cline{2-6}  & **Type** & **(This Study)** & **(Literature)** & **Ref.** & **Consistency** \\ \hline Oils 5–7 & Amides (polar) & \(\sim\)38–41 mN/m & 35–40 mN/m & [23; 25] & High \\ Oils 8–10 & Ethers (less polar) & \(\sim\)43–46 mN/m & \(\sim\)40–45 mN/m & [23; 32] & Moderate \\ Oils 1–4 & Alkanes (non-polar) & \(\sim\)50–52 mN/m & \(>\)50 mN/m & [23; 26] & High \\ Oils 11–14 & Aromatics (non-polar) & \(\sim\)51–54 mN/m & \(>\)50 mN/m & [23; 25] & High \\ \hline \hline \end{tabular}
\end{table}
Table 5: Simulated vs. literature IFT values for selected oil–water systems.  
In contrast, both the alkane oils (Oil 1-4) and the aromatic oils (Oil 11-14), which exhibited minimal polarity and interfacial activity, showed a lower tendency to form stable emulsions. Among these, only 8 out of 12 alkane models and 3 out of 12 aromatic models achieved successful HIPE formation, indicating the critical importance of oil polarity and structural composition in emulsion stability (Figure 4(a3-c4)).  
Figure 4: Morphological evolution of high internal phase emulsions (HIPEs) for various emulsifier–oil combinations: (**a1–c4**) representative porous frameworks formed with amide, ether, alkane, and aromatic oils using AS1, AS2, and AS3 emulsifiers. The inset in (**a1**) shows non-bonding distances (3.06 Å and 3.45 Å) between oil heteroatoms and AS1. RDF curves between oil and emulsifier are presented between (**a1**) and (**b1**).