## 3 Results
### Measurements of Magnitude Level of Skin Bioimpedance
Figure 16: The magnitude of total electric bioimpedance versus frequency for all bioimpedance sensors for subject LTD. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \multirow{2}{*}{**Frequency,**} & \multicolumn{3}{c}{**Impedance, [k\(\Omega\)]**} & \multicolumn{3}{c}{**Impedance, [k\(\Omega\)]**} & \multicolumn{3}{c}{**Impedance, [k\(\Omega\)]**} \\  & \multicolumn{3}{c}{**Subject 1 LPD**} & \multicolumn{3}{c}{**Subject 2 CB**} & \multicolumn{3}{c}{**Subject 3 FB**} \\ \cline{2-10}  & **PPY** & **10\%Ag/** & **20\%Ag/** & **PPY** & **10\%Ag/** & **20\%Ag/** & **PPY** & **10\%Ag/** & **20\%Ag/** \\  & & **PPY** & **PPY** & **PPY** & **PPY** & **PPY** & **PPY** & **PPY** & **PPY** \\ \hline \(1\) & 16 & 31.40 & 41 & 155 & 174 & 380 & 80 & 164 & 220 \\ \(10\) & 3.87 & 6.41 & 12 & 24 & 25.80 & 43 & 15.54 & 25.70 & 31.30 \\ \(50\) & 1.82 & 1.87 & 3.24 & 7.12 & 6.64 & 10 & 5.30 & 6.40 & 7.20 \\ \(100\) & 1.42 & 1.10 & 2 & 4.28 & 3.64 & 4.80 & 3.37 & 3.53 & 3.92 \\ \(120\) & 1.31 & 0.944 & 1.70 & 3.60 & 3.07 & 4.60 & 2.95 & 2.38 & 3.42 \\ \(150\) & 1.18 & 0.796 & 1.47 & 3 & 2.52 & 3.52 & 2.52 & 2.05 & 2.75 \\ \(200\) & 1.00 & 0.661 & 1.04 & 2.34 & 1.98 & 2.71 & 2.09 & 1.87 & 2.11 \\ \(250\) & 0.90 & 0.571 & 0.88 & 1.92 & 1.67 & 2.25 & 1.75 & 1.55 & 1.84 \\ \(300\) & 0.82 & 0.512 & 0.79 & 1.67 & 1.44 & 1.80 & 1.52 & 1.33 & 1.44 \\ \hline \end{tabular}
\end{table} 
Table 3: The measurements of magnitude level of total bioimpedance, i.e., for skin bioimpedance in series with two electrodes impedance, the data is corresponding for three bioimpedance sensors made with sensitive materials: PPY and 10%Ag/PPY and 20%Ag/PPY hybrid nanocomposites. Figure 17: The magnitude of total electric bioimpedance versus frequency for all bioimpedance sensors, for subject CB. Figure 18: The magnitude of total electric bioimpedance versus frequency for all bioimpedance sensors for subject FB. In addition, it is worth mentioning that on the analysed frequency range, were observed lower bioimpedance values for the male subjects compared to the bioimpedance values obtained for the female subjects, resulting in a different behaviour between the two sexes in terms of bioimpedance. A comparative evaluation of results with the literature considered another polymeric material, namely PDMS [46]. A flexible dry electrode for long-term EEG measurement based on PDMS material was realised and tested. The magnitude of total electric bioimpedance was measured by using two electrodes were placed on skin separately (about 3 cm), and then current is applied to measure impedance (Figure 19). The signal of LCR meter is set to 2 V and the frequency range of 20 Hz-10 kHz. In this study, 10 tests on five different participants are performed [46]. The results of these measurements are shown in Figure 20.  
Both AgNPs/PPY hybrid nanocomposites as well as PDMS presented a tendency to decrease with frequency of the measured skin bioimpedance. Due to the obstruction of the polymer electron gaps by Ag NPs, the bioimpedance values in the frequency range of 1-300 kHz were higher compared to the behaviour of PDMS in the frequency range of 20 Hz-10 kHz. For both hybrid nanocomposites 10%Ag/PPY and 20%Ag/PPY as well as for PDMS the results obtained indicated a good tendency of quasi-linear decreasing of the electric skin bioimpedance with frequency. Figure 19: Schematic diagram of measurement circuit for magnitude of total electric bioimpedance versus frequency (adapted from [46]).