2.4.5. Electrical Properties

The electrical properties, specifically the dielectric constant (εr) which is the real part of the relative permittivity, electrical conductivity (σ), and dielectric losses (tanδ) were evaluated with an LCR meter (IM 3533 HIOKI, Japan) in the frequency range 100–105 Hz. Each sample, with a thickness of approximately 200 ± 50 μm, was placed among two indium tin oxide electrodes (1 cm diameter) and supplied with 1 V. The dielectric constant can be calculated from [17]:

$$
\varepsilon'\_{\rm r} = \frac{\mathbf{C}t}{\varepsilon\_0 \mathbf{A}} \tag{4}
$$

where *C*, *t*, *A*, and ε0 are the capacitance of the sample, thickenss, the contact area of the electrode, and permittivity of free space (8.854 × 10−<sup>12</sup> Fm−1), respectively. The electrical conductivity σ is calculated using the equation:

$$
\sigma = \mathcal{G}\left(\frac{t}{A}\right) = 2\pi f \varepsilon\_0 \varepsilon'\_{\rm r} \tan \delta \tag{5}
$$

where *G* is the conductance and *f* is the applied frequency. The dielectric loss tangent (tanδ) can be estimated from the relationship:

$$\tan \delta = \frac{\varepsilon''\_{\text{r}}}{\varepsilon \nu\_{\text{r}}} \tag{6}$$

Here, <sup>ε</sup>r is the imaginary component of relative permittivity.
