## 3 Results  
### Analysis of OA-ZnO NPs  
TEM and SEM images of the prepared ZnO NPs in Figure S1A,B show the spherical particles with an average size of 11.8 \(\pm\) 1.8 nm. However, large aggregates of as-made ZnO NPs were observed in both micrographs, possibly caused by the hydrophilic interaction among hydroxyl groups on the particle surface [7; 20]. The XRD pattern in Figure S1C displays the well-defined peaks at 31.7\({}^{\circ}\), 34.4\({}^{\circ}\), 36.2\({}^{\circ}\), 47.4\({}^{\circ}\), 56.5\({}^{\circ}\), 62.8\({}^{\circ}\), 66.0\({}^{\circ}\), 67.9\({}^{\circ}\), and 69.1\({}^{\circ}\), corresponding to the diffractions of (100), (002), (101), (102), (110), (103), (200), (112), and (201) planes of ZnO, respectively. The good agreement between the standard diffraction peaks and the obtained peaks indicated the successful preparation of the ZnO in nanoscale [21]. The high purity of the synthesized product was confirmed by the similar standard pattern. Moreover, this diffraction pattern indicated the good crystalline nature in the hexagonal structure of resulting materials [2]. To reduce the agglomeration of ZnO NPs, and to improve its dispersibility in monomer droplet, the particle surface was modified with the commonly used coupling agent, i.e., OA. TEM images of OA-ZnO NPs, having various OA contents, are shown in Figure 1A-D. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**System**} & \multicolumn{3}{c}{**Competition**} & \multirow{2}{*}{**Particle Size**} & \multirow{2}{*}{**Zero Potential**} & \multirow{2}{*}{**\begin{tabular}{} \end{tabular}**} & \multirow{2}{*}{**\
\begin{tabular}{} \end{tabular}**} & \multirow{2}{*}{**
\begin{tabular}{} \end{tabular}**} & \multirow{2}{*}{**Morphology**} \\ \cline{2-2} \cline{6-7}  & & & & & & & & \\ \hline
1 & St & - & 0.5\% & 0.5\% & 206.5\(\pm\) 2.68 & -261.1\(\pm\) 13 & 32.7\({}^{\circ}\) & Flishing like \\
2 & St & - & 0.5\% & 1.5\% & 196.4\(\pm\) 4.3 & -36.8\(\pm\) 0.2 & 128 & Flishing like \\
3 & St & - & 0.5\% & 1.0\% & 1.4\% & -33.2\(\pm\) 0.3 & 15.4\(\pm\) 0.2 & Flishing like \\
4 & St & - & 1.5\% & 1.5\% & 196.2\(\pm\) 0.1 & -32.8\(\pm\) 0.5 & 122 & Flishing like \\
5 & St & - & 2.5\% & 1.5\% & 1743.4\(\pm\) 4.2 & -37.2\(\pm\) 0.2 & 8.9\({}^{\circ}\) & Flishing like \\
6 & St & 1\% & 0.5\% & 1.5\% & 1823.3\(\pm\) 0.9 & -122.2\(\pm\) 5.3 & 26.9\({}^{\circ}\) & Flishing like \\
7 & St & 9\% & 0.5\% & 1.5\% & 3420.6\(\pm\) 4.3 & -176.4\(\pm\) 4.1 & 18.5\({}^{\circ}\) & Combined \\
8 & St & 10\% & 0.5\% & 1.5\% & 1820.6\(\pm\) 0.2 & -187.5\(\pm\) 5.4 & 21.9\({}^{\circ}\) & Flishing like \\
9 & Mkola & 1\% & 0.5\% & 1.5\% & 1320.6\(\pm\) 0.2 & -22.0\(\pm\) 0.5 & 69.3\({}^{\circ}\) & Flishing like \\
10 & Mkola & 9\% & 0.5\% & 1.5\% & 1189.2\(\pm\) 2.8 & -223.3\(\pm\) 0.5 & 69.8\({}^{\circ}\) & Hollow \\
11 & Mkola & 10\% & 0.5\% & 1.5\% & 1189.2\(\pm\) 2.8 & -309.8\(\pm\) 0.8 & **42.5** & Hollow \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Formula of ZPPs with relevant characteristics, i.e., average particle size from TEM, zeta potential, and %weight residue from TGA. The better dispersion of ZnO NPs was obtained when the added OA was higher than 0.01 mL. The adsorbed OA broke up the agglomerates by decreasing their surface energy and by increasing steric repulsion [22]. TGA thermograms in Figure 1E confirmed the existence of OA in the synthesized OA-ZnO NPs. The weight loss of the bare and the four samples of OA-ZnO NPs with the added OA of 0.01, 0.04, 0.10, and 0.40 mL, in the range of 150-700 \({}^{\circ}\)C, were 2.5, 3.1, 3.3, 3.0, and 4.8%, respectively. The high decomposition rate of OA-ZnO NPs with 0.40 mL OA (0.0004 mg/min) in Figure S2 further confirmed the high amount of OA on ZnO NPs surface compared to bared ZnO NPs and the other OA-ZnO NPs (0.0002 mg/min). The rapid weight loss at ca. 350 \({}^{\circ}\)C was due to the decomposition of adsorbed OA molecules [23].