## 3 Results and Discussion
The SEM-EDS elementary analysis results of the carbon nanotubes are shown in Table 4. The effectiveness of PDMS adsorption is evidenced by the decrease in the carbon content from 92.96% to 88.37% with the simultaneous increase in the contents of oxygen and silicon, which are the polymer constituents. The remaining elements such as Mo or Fe are probably impurities left over from the nanotube synthesis process or introduced during the analysis. The SEM images of samples #4 and #7 are shown in Figure 10. Both images show amorphous silica nanoparticles formed on the surface. More regular arrangement and larger sizes were obtained on surface #4 produced by the dip-coating method (Figure 10a). In the case of surface #7, which was coated manually, the nanoparticles are smaller, and the coverage of the support is heterogeneous. In both cases, the carbon nanotubes (filler particles) cannot be seen on the surface; this means that they are built into the bulk structure of the coating, which will be also confirmed by the XRD analysis (Figure 11). Figure 9: SEM images of MWCNTs: nonmodified (**a**) and modified with PDMS (**b**). The XRD pattern of sample #4 is presented in Figure 11. There can be observed as a much broadened peak over the 20 range of 20-30\({}^{\circ}\), which corresponds to the amorphous silica structures on the surface [64]. However, the peaks at 32\({}^{\circ}\) (100 plane) and 66\({}^{\circ}\) also indicate the presence of trigonal silica [65]. This means that during the coating fabrication by the TEOS hydrolysis under the applied conditions, two forms of silica are created. As it was mentioned above, the XRD analysis showed no nanotubes in the top layer of the coating. The XRD patterns for the MWCNTs should appear at around 26\({}^{\circ}\) (indexed as 002 reflection of the hexagonal graphite structure) and 43\({}^{\circ}\) (100 graphitic planes) [66; 67], but there is a lack of them. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Element 1** & **MWCNTs** & **MWCNTs + PDMS** \\ \hline C & 92.96 & 88.37 \\ O & 5.14 & 7.01 \\ Si & 0.46 & 3.13 \\ Mo & 0.39 & 0.45 \\ Fe & 1.06 & 0.89 \\ \hline \hline \end{tabular} 1  
\end{table} 
Table 4: SEM-EDS elementary analysis of carbon nanotubes (MWCNTs): nonmodified and modified with PDMS. Figure 11: XRD pattern of the sample #4. Figure 10: SEM images of the sample #4 (**a**) and #7 (**b**). As it is presented in Figure 12, the optical properties of the samples investigations show the formation of largely transparent composite films in the case of the samples produced by the dip-coating technique. The transmittance values of samples #1-#6 remain at about 95%. This value is a few percent smaller than for silica (pure polysiloxane coatings) without any filler [42]. However, it should be emphasized that the coatings include carbon nanotubes, the suspension of which during the stability tests revealed no transmission. Moreover, the differences are not significant, and furthermore, the transmission values are greater than for the uncoated glass substrate [42]. For manually applied coatings, the transmission is equal to 70% and only 30% for samples #7 and #8, respectively. This is due to the greater thickness and structure of the coatings, which was confirmed by the above optical profilometry, and therefore more nanotubes concentration in the optical path. The effects observed in the wavelength range of 190-350 nm and at 580 nm [68] were described in detail in our previous paper [42].