## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **\#1** & **\#2** & **\#3** & **\#4** & **\#5** & **\#6** & **\#7** & **\#8** \\ \hline R\({}_{\text{a}}\) [nm] & 3.61 & 8.51 & 6.48 & 2.68 & 5.40 & 7.36 & 703.45 & \(2.670\times 10^{3}\) \\ R\({}_{\text{q}}\) [nm] & 4.81 & 11.41 & 14.23 & 4.78 & 9.88 & 12.09 & 795.61 & \(4.280\times 10^{3}\) \\ \hline S\({}_{\text{a}}\) [nm] & 1.69 & 4.289 & 5.48 & 2.06 & 4.11 & 5.13 & 703.00 & \(2.674\times 10^{3}\) \\ S\({}_{\text{q}}\) [nm] & 3.05 & 6.473 & 13.83 & 4.36 & 9.11 & 10.37 & 796.00 & \(4.277\times 10^{3}\) \\ S\({}_{\text{sk}}\) & 6.77 & 1.426 & \(-8.57\) & 6.72 & 7.91 & 7.07 & 0.24 & 2.89 \\ S\({}_{\text{sk}}\) & 104.25 & 25.253 & 70.91 & 81.48 & 142.70 & 118.27 & 5.23 & 18.70 \\ S\({}_{\text{dq}}\) [deg] & 0.04 & 0.06 & 0.27 & 0.06 & 0.14 & 0.16 & 9.82 & 48.19 \\ S\({}_{\text{df}}\) [%] & 0 & 0 & 0.001 & 0 & 0 & 0 & 1.14 & 46.04 \\ S\({}_{\text{sk}}\) [1/mm\({}^{2}\)] & 339.01 & 546.797 & 162.36 & 467.72 & 350.79 & 418.09 & 1417.47 & 1195.38 \\ S\({}_{\text{tr}}\) & 0.68 & 0.819 & 0.74 & 0.73 & 0.74 & 0.77 & 0.78 & 0.73 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Linear and areal roughness parameters of the obtained surfaces. coating #5 is described by a larger S\({}_{\rm dq}\) value (0.14\({}^{\circ}\)) than #2 (0.06\({}^{\circ}\)), which corresponds to the height maps in Figure 8; visually, there are more peaks on surface #5. S\({}_{\rm dq}\) can be also associated to the wetting degree of surface by various fluids. The developed interfacial area ratio (S\({}_{\rm dr}\)) describes in percentage the increasing surface area after applying coating compared to the flat surface of the support. It can be concluded that in the case of the samples produced by dip-coating, there are only microroughness due to  
Figure 8: 3-D height maps of the obtained surfaces (sample number above the image). small \(\mathrm{S_{dr}}\) values, while on surfaces #7 and #8, there is macroroughness resulting from an increase in the surface area of up to about 10% and 50%, respectively. This confirms the summit density (\(\mathrm{S_{ds}}\)) parameter, which corresponds to the number of summits per unit area making up the surface. Samples #1-#6 are described by smaller values of the \(\mathrm{S_{ds}}\) due to single and sharp peaks, while samples #7 and #8 have wider summits. The texture aspect ratio (\(\mathrm{S_{tr}}\)) evaluates directionality of the surface texture. For all samples, the \(\mathrm{S_{tr}}\) values are greater than 0.5 with an average of 0.75, which indicates that the surfaces textures do not have periodicity in the specific direction. Regardless of the type of plasma, the modification of the substrate causes an increase in the surface roughness (characterized by the \(\mathrm{R_{q}}\) or \(\mathrm{S_{q}}\) parameter), and the effect is the most noticeable in the case of argon plasma. Coatings #1-#3 and #4-#6 were applied with the dip-coating technique with the withdrawal speed equal to 50 mm/min and 20 mm/min, respectively. The differences in the withdrawal speed result in various thicknesses of the obtained layers [62]. In the case of the silica coatings prepared by the acid-assisted TEOS hydrolysis, the withdrawal speed in the range of 20-80 mm/min is referred to as the critical withdrawal speed. The value of 50 mm/min allows to get homogeneous, transparent, and crack-free silica coatings of a minimum film thickness [63]. The approximate thickness of the coatings in the case of its deposition by the dip-coating technique is about 0.46 \(\upmu\)m, while for the manual immersion or spreading, it is about 0.79 \(\upmu\)m.  
The scanning electron microscopy images of the multiwalled carbon nanotubes are shown in Figure 9. In Figure 9a, the pristine nanotubes with a diameter of about 20 nm are presented. In Figure 9b, the MWCNTs/PDMS composite is presented. An increase in the diameter of the nanotubes and characteristic shading can be observed as a result of the PDMS adsorption.