## 3 Results
### Computational Data  
Examining the obtained \(\chi\) and Emix values from computational analyses (Table 2) lead us to observe the following swelling capacity trends for the four ethers that were incorporated in this study: CPME \(>\) MTBE \(>\) 2-MeTHF \(>\) DEE. It was observed that the Emix and \(\chi\) values of 2-MeTHF lie in the region of the \"bad\" solvents, next to DEE, and even higher than the MTBE. This could explain the unexpected behaviour of 2-MeTHF and the incompatibility of PS resin towards this ether, especially after a SPPS protocol. These results agree with the fact that the osmotic shock did happen, and the morphological structure of the resin was altered and appeared as dented tracks characteristics (Figure 3C). For the rest of the ethers that were used in this study, CPME has the lowest Emix and \(\chi\) values, which again explains the great performance and compatibility of this green ether over the others, whereas DEE occupies the highest Emix and \(\chi\) values, hence it was the worst ether in this study. MTBE values are smaller than 2-MeTHF and closer to CPME; however, due to its dissimilar solubility parameter, it is considered as a \"bad\" solvent was previously realized from the experimental data. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameter/Solvent** & **DEE** & **2-MeTHF** & **MTBE** & **CPME** \\ \hline Emix kcal/mol (at 280 K) & 30.9 & 27.4 & 23.8 & 18.5 \\ Chi (\(\chi\)) (at 280 K) & 55.5 & 49.3 & 42.8 & 33.2 \\ \hline \hline \end{tabular} Blends module, Base: CTC resin; Screen: ether. Geometry optimization done by the Forcite module. “Dreiding forcefield” and “Charge using QEq” were chosen in both of the tests.  
\end{table} 
Table 2: Emix and Chi (\(\chi\)) values of each ether and the CTC resin. Figure 4: Three-dimensional (3D) Atomistic structure of 1% divinylbenzene (DVB) crosslinked polystyrene (PS) showing: (**A**) the locations of crosslinks; and, (**B**) the DVB monomer. To better understanding the behavior of the ethers, additional computational analyses were carried out. For instance, the dependence of the \(\chi\) and Emix parameters on the temperature was estimated as a function of temperature when considering 25 steps covering (50-500 K). The calculations showed that, for all of the examined ethers, the lower \(\chi\) values (good swelling capacity) are likely associated with a temperature as high as 400 K and more; however, such high temperatures do not apply to our experimental conditions, alternatively, as low as 280 K is considered in our experimental procedure. As the temperature goes down, the situation was the opposite, in which higher \(\chi\) values (worse swelling) are likely more favoured. However, and surprisingly, CPME and MTBE have shown an exceptional trend in a temperature range starting from 270 K to as low as 86 K, where low \(\chi\) values (good swelling capacity) with these two ethers are also anticipated in the case of temperature reduction. However, at temperatures below 86 K, the normal trend of high \(\chi\) values is operating again; nevertheless, this exceptional trend is advantageous in our work, as it is operating in a range that covers the working temperature of our study. These calculations explain the experimental data of all the ethers examined in this study, most importantly, the situation of 2-MeTHF. Provided that, for the sake of enhancing the precipitation process, a chilled ether is usually considered rather than a warm one, where the precipitation step is usually carried out at \(-18\)\({}^{\circ}\)C (280 K). Thus, the computational data are in line with the experimental findings that consider DEE and 2-MeTHF as \"bad\" solvents, because they possess high \(\chi\) values at low temperatures (Figure 5A,B). Despite the fact that MTBE is also showing an interesting reduction trend of \(\chi\) values as the temperature goes as low as 86 (Figure 5C), it is considered to be \"bad\" solvent due to its overall high \(\chi\) values in addition to its dissimilar solubility parameter.