## 3 Results
### Characterization of Copolymers
This probably explains why upon the following same polymerization conditions: molar ratio of monomers, amount of PS seed, and toluene, the microspheres produced from TRIM are of higher diameter than those obtained with \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Copolymer**} & \multirow{2}{*}{**\%N**} & \multicolumn{3}{c}{**N\({}_{\text{2}}\) Adsorption-Desorption**} & \multicolumn{3}{c}{**ISEC**} \\ \cline{3-8}  & & **S\({}_{\text{BET}}\)** [m\({}^{2}\)/g] & **V\({}_{\text{p}}\)** [cm\({}^{2}\)/g] & **PSD\({}_{\text{max}}\)** [nm] & **V\({}_{\text{p}}\)** [cm\({}^{3}\)/g] & **V\({}_{\text{micro}}\)** [cm\({}^{3}\)/g] & **PSD\({}_{\text{max}}\)** [nm]** \\ \hline poly(4 VP-_co_-14 DMB) & 5.56 & 89 & 0.26 & 4/50 & 0.81 & 0.12 & 1-2/17 \\ poly(4 VP-_co_-TRIM) & 4.32 & 147 & 0.29 & 4/34 & 0.77 & 0.14 & 1-2/30 \\ poly(St-_co_-DVB) & - & 225 & 0.38 & 4/24 & 0.51 & 0.18 & 1-2/41 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Percentage of nitrogen content and parameters characterizing porous structure of 4 VP copolymers and poly(St-co-DVB) determined by means of nitrogen adsorption-desorption method and ISEC. Figure 3: \({}^{13}\)C CP/MAS NMR spectrum of poly(4 VP-_co_-14 DMB). 14 DMB. In addition, images of poly(St-_co_-DVB) microspheres are presented in Figure 4. These microspheres were obtained as reference materials with a highly hydrophobic nature. On the basis of the obtained images of the surface and the internal topography of the microspheres, it can be clearly stated that the newly synthesized materials show a porous character. The outer layer of microspheres is not smooth; large pores are observed. The interior of the particles reveals a fine-grained, tightly packed structure with empty spaces that create pores connected with tunnels. Such an internal structure is characteristic of crosslinked polymers [29]. However, considering the internal structure of 4 VP copolymers and poly(St-_co_-DVB) microspheres, some differences are noticeable. In the interior of the poly(St-_co_-DVB) microsphere, the grains are smaller and more homogenously packed, and the voids between them are smaller than in the case of 4 VP microspheres. The probable reason for these differences is the affinity of used monomers to the PS seed. St and DVB are hydrophobic monomers chemically similar to the PS. During the formation of porous copolymeric microspheres, the PS seed is swollen with the monomer mixture and, together with toluene, acts as a porogen. As polymerization proceeds, the phase separation between the formed crosslinked network of the copolymer and the surrounding liquid phase containing monomers and porogens occurs [30]. The resulting microgels, called nuclei, combine and agglomerate to form small domains that are tightly packed and form the final microsphere. When PS is swollen with compatible monomers--St and DVB, the microgels are homogeneously distributed in the liquid phase leading to the homogenous internal grain structure of poly(St-_co_-DVB) with small pores. On the other hand, the 4 VP and methacrylate crosslinkers are less hydrophobic than PS seed. The resulting nuclei interact more with each other than with PS and form larger agglomerates connected with larger pores. The conducted analysis of porosity by means of N\({}_{2}\) adsorption-desorption measurements showed that the prepared copolymers possess a developed, permanent porous structure. From Table 1, it follows that 4 VP copolymers have a smaller specific surface area and pore volume than poly(St-_co_-DVB). The PSD\({}_{\text{max}}\) for poly(St-_co_-DVB) is also smaller than for methacrylate copolymers (Figure 5a). This finding can be explained by the above-mentioned mechanism of porous structure formation. Since St and DVB monomers are absorbed easier and more homogenously by PS seed than 4 VP and methacrylate crosslinkers, the smaller aggregates connected with smaller pores are formed.