*3.10. Electrical Measurements*

In order to determine the effect of polyaniline on the electrical properties of the fibers, resistance tests were carried out. The resistance of fibers on the 0.3 cm section was measured using the constant current method, and the results were given as mass-specific resistance Rs ( Ωg/cm2) (8). This is a parameter used to describe fiber resistance [42]. This measure allows the electrical properties of fibers to be shown in relation to their construction, and not geometric parameters (such as diameter), which are difficult to determine in yarns composed of many fibrils.

$$\text{Rs} = \frac{\text{RN} \text{m}\_{\text{l}}}{\text{l} \times 10^5 \text{ }^\circ \text{C}} \tag{8}$$

where R is the resistance of the sample, N is the number of fibers in the yarn, ml is the linear mass (tex) = (g/km), and l is the length of the sample (cm).

Standard polyacrylonitrile (reference) fibers are dielectrics with a resistance of 10<sup>11</sup> Ω (Table 7). Both types of fibers doped with polyaniline were tested for resistivity. In the case of the PAN/PANI blended fibers, no change in the fiber resistance was observed, whereas the PAN/PANI in situ fibers were characterized by mass-specific resistances of 5.47 k Ωg/cm2. These fibers, as shown by the FTIR, XRD, and TG studies, consisted of two phases of different polymers, which were additionally visible in the SEM images. In these fibers, the polyacrylonitrile matrix was responsible for the mechanical properties and thermal stability of the fibers. Polyaniline was responsible for their electrical conductivity.

In order to compare the obtained results with literature data, it can be assumed that the conductance of the obtained PAN/PANI in situ fibers is of the order 10−<sup>4</sup> Scm−1. This conductance value is lower than that of pure PANI fibers. According to literature data, polyaniline fibers have conductance on the order of 10–100 Scm−<sup>1</sup> [43,44], but mechanical properties of these fibers are weak. Better mechanical properties, but lower conductance, usually is obtained in composite fibers. Topta¸s et al. obtained composite PAN/PANI fibers in a different method that was presented in this paper, but mechanical and electrical properties are comparable [14].


**Table 7.** Electrical properties of obtained fiber.
