*3.4. Conductivity Test*

The POA/BaSO4 nanocomposites were subjected to the measurement of electrical conductivity by the conductivity meter. The electrical conductivity of the nanocomposites depends upon the properties of the individual components and also depends on the temperature factor.

Table 2 shows the electrical conductivity of POA at 1080 S/m. The electrical conductivities of the POA/BaSO4 nanocomposites determined were lower than the pure POA. The nanocomposite with 1% of loading of the BaSO4 nanoparticles showed conductivity at 992 S/m. Other nanocomposites containing 3%, 5%, 7%, and 10% of loading of BaSO4 NPs exhibited conductivity at 919, 843, 784, and 578 S/m respectively (Figure 5). These results not only confirm the presence of nanoparticles but also show that the increase in the percentage of the BaSO4 nanoparticles in the composites results in a decrease in the conductivity of the materials [17]. The addition of barium sulfate in poly(*o*-anisidine) allowed the composite properties to be tunable, which can be used for designing the sensor materials for future use.

**Figure 3.** UV-visible spectra of (**a**) pure POA, (**b**) 1% of POA/BaSO4, (**c**) 3% of POA/BaSO4, (**d**) 5% of POA/BaSO4, (**e**) 7% of POA/BaSO4, and (**f**) 10% of POA/BaSO4.

**Figure 4.** TEM micrograph of BaSO4 nanoparticles.


**Table 2.** Scheme of conductivity test.

**Figure 5.** The plot of conductivity and nanoparticles' percentage relationship.
