## 2 Materials and Methods
### Synthesis of Microcapsules  
The acrylate monomers employed are listed in Table 1, where their MW is calculated as the average number of acrylate moieties per molecule. Monomer A consists of an aromatic hexafunctional urethane acrylate, monomer B is Dipentaerythnitol pentaacrylate, while monomer C is 1,2-(triglycolate diacrylate) ethylene glycol. The detailed composition of the batches under investigation is shown in Table 2. The monomer mixture employed is the sole parameter that differed in making the various samples. Precisely, the monomer composition and weight proportion variations are introduced to establish a structure-performance correlation. For the sake of clarity, the names of the samples are defined as follows: CAP\(\mid\)A\(\mid\)B\(\mid\)C\(\mid\)I, where A, B, and C correspond to the weight ratio of Monomer A, Monomer B, and Monomer C.  
The core/wall ratio for all the samples equals 95/5, where the core is defined as the weighted sum of the fragrance and IPM, while the wall is defined as the sum of acrylic monomers. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample Name** & \multicolumn{3}{c}{**Monomer Mixture Composition**} \\  & **\% A** & **\% B** & **\% C** & **Core:Wall Ratio** \\ \hline CAP\(\mid\)1\(\mid\)1\(\mid\)0\(\mid\)1 & 100 & 0 & 0 & 95:5 \\ CAP\(\mid\)0\(\mid\)1\(\mid\)1\(\mid\)0\(\mid\) & 0 & 100 & 0 & 95:5 \\ CAP\(\mid\)0\(\mid\)3\(\mid\)0\(\mid\)7\(\mid\)0\(\mid\)1 & 30 & 70 & 0 & 95:5 \\ CAP\(\mid\)0\(\mid\)5\(\mid\)0\(\mid\)5\(\mid\)0 & 50 & 50 & 0 & 95:5 \\ CAP\(\mid\)0\(\mid\)0\(\mid\)1\(\mid\)1 & 0 & 0 & 100 & 95:5 \\ CAP\(\mid\)0\(\mid\)3\(\mid\)0\(\mid\)0\(\mid\)7\(\mid\)1 & 30 & 0 & 70 & 95:5 \\ CAP\(\mid\)0\(\mid\)5\(\mid\)0\(\mid\)0\(\mid\)5\(\mid\) & 50 & 0 & 50 & 95:5 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Monomer composition of capsules synthesized. The capsules were synthesized via an in-situ polymerization process [19]. It consists of the dispersion of one phase containing a reactive monomer into a second immiscible phase [20]. Hence, two immiscible phases were prepared: water and oil phases, as shown in Figure 1.  
A preliminary oil phase, consisting of 42.9 g of fragrance mixture A and 5.84 g of the acrylate monomer mixture reported in Table 2, was mixed until the monomer was fully dissolved. A second oil phase consisting of 26.9 of fragrance mixture A, 50.21 g isopropyl myristate (IPM), and 1.8 g of oil-soluble initiators (precisely 1.0 g 2,2'-azobis [2-methylbutyronitrile] and 0.8 g 4,4'-2,2'-Azobis[2-methylpropionitrile]) was prepared separately and mixed until complete homogenization. The two oil phases were then mixed at 500 rpm with an overhead stirrer Eurostar 200 digital from IKA (Staufen, Germany) using a 90-degree 4-blade stirrer [19]. The water phase, containing 178.6 g of a 2% water PVOH solution, 0.67 g of the water-soluble initiator (4,4'-azobis[4-cyanovaleric acid]), and 0.79 g of 21.5% NaOH, was prepared and mixed with an IKA Eurostar power control visc E20-MX-1 at 3000 rpm until the 4,4'-azobis[4-cyanovaleric acid] dissolved. The water phase was added to the oil phase, and high shear agitation was applied to produce an oil-in-water (O/W) emulsion using an overhead stirrer Eurostar 200 digital from IKA (1200 rpm) with a 90-degree four-blade stirrer for 30 min. The emulsion was included in a glass jacketed flask reactor vessel of 500 mL equipped with a reflux condenser and overhead anchor stirrer. The temperature was increased to 75 \({}^{\circ}\)C in 30 min, held at 75 \({}^{\circ}\)C for 4 h, increased to 95 \({}^{\circ}\)C in 30 min, and held at 95 \({}^{\circ}\)C for 6 h. Finally, the batch was allowed to cool to room temperature. As a result, a population of microcapsules dispersed into the aqueous phase was obtained, which is herein defined as capsule slurry. As represented in Figure 2, the wall's growth occurs within the oil phase, as the monomer is a component of the oil phase.