## 3 Results and Discussion
### Mesporosity of Nanocomposites and Their Specific Surface and Specific Pore Volume  
It has been established that nanoscale pores in biomedical materials can allow drugs with a small molecular weight (molecule size 1-2 nm) and proteins (2-10 nm) to diffuse slowly [50; 51]. In case of micron-sized pores, drugs and proteins spread much faster. In addition, nanoscale pores can be used to control the biodegradation of an implant, since they significantly increase its surface area [52; 53]. There are also studies where nanoporous scaffolds that mimic the architecture of the native extracellular matrix can remain unnoticed by the body's immune system [54].  
To study the distribution of nanoscale pores, the most homogeneous fragment with a volume of \(\sim\)1 mm\({}^{3}\) was isolated from the nanocomposites. This fragment was selected based on microCT studies. Figure 5a shows nitrogen adsorption isotherms at 77 K in nanocomposites based on both types of SWCNT and both concentrations. All isotherms had capillary-condensation hysteresis, which indicates the presence of through mesopores in the samples. The size distributions of nanoscale pores, the specific surface area and the specific pore volume were calculated using the Barrett-Joyner-Halenda (BJH) method [55]. The mesopore size distribution is shown in Figure 5b.  
The values of specific surface area, specific volume and distribution of pore diameters in nanocomposites are shown in Table 2. The nanocomposite with a lower concentration of SWCNT1 (0.001 wt.%) showed the largest specific surface area and specific pore volume. The nanocomposite based on SWCNT2 (0.001 wt.%) also demonstrated a high specific surface area. An increase in the concentration of both types of nanotubes leads to a decrease in the specific surface area and specific pore volume. This may be due to the oversaturation of nanocomposites with tubes. The formation of mesopores can be primarily associated with the formation of inhomogeneities around the nanotubes of their bundles during the absorption of laser radiation by the nanotubes and the conversion of its energy into  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Structure Parameters**} & \multicolumn{4}{c}{**Type and Concentration of Nanotubes in the Composition of Nanocomposite**} \\ \cline{2-5}  & **SWCNT1 (0.001 wt.\%)** & **SWCNT1 (0.01 wt.\%)** & **SWCNT2 (0.001 wt.\%)** & **SWCNT2 (0.01 wt.\%)** \\ \hline Minimum pore diameter (\(\mu\)m) & 14 & 38 & 31 & 47 \\ \hline Maximum pore diameter (\(\mu\)m) & 82 & 124 & 318 & 186 \\ \hline Average pore size (\(\mu\)m) & 48 & 86 & 101 & 73 \\ \hline Porosity (\%) & 44 & 61 & 68 & 77 \\ \hline The proportion of open pores (\%) & 21 & 24 & 15 & 18 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Quantitative parameters of the internal nanocomposites structure obtained using microCT.  
Figure 5: Nitrogen adsorption isotherms at 77 K (**a**) and pore size distribution (**b**) in nanocomposites: SWCNT1 (0.001 wt.%)—curves 1, SWCNT1 (0.01 wt.%)—curves 2, SWCNT2 (0.001 wt.%)—curves 3, SWCNT2 (0.01 wt.%)—curves 4.  
heat. We have previously demonstrated a similar effect when exposed to pulsed laser radiation on biopolymer dispersions of SWCNT [47]. From the dependences of the pore size distribution presented in Figure 5b, it can be seen that the curves are polymodal. The largest scatter of pore sizes was obtained for nanocomposites based on SWCNT1 (0.001 wt.%). However, the majority of mesopores in these nanocomposites were in the ranges of 5-20 and 30-50 nm (Table 2). An increase in concentration to 0.01 wt.% promoted a decrease in the specific surface area and pore volume in nanocomposites based on SWCNT1 and SWCNT2. Moreover, an increase in the size of the nanotubes themselves and their bundles affected the decrease in the specific surface area and pore volume. The sample based on large SWCNT2 and their bundles had pores with a size close to 100 nm. Such pores cannot be called mesopores, since their sizes were mainly in the ranges of 85-100 and 95-100 nm.