*3.4. X-ray Diffraction*

The most efficient method for analyzing the structure and nature of materials is XRD. The XRD spectrum of PPy is shown in Figure 5a. A broad peak can be seen at 2θ = 29.73◦. This is PPy characteristic peak. The scattering of X-rays from PPy chains at interplaner spacing causes the peak to expand [36]. Broad peaks in the CPs are normally thought to suggest a semicrystalline structure. The PPy average chain separation from the maxima may be calculated using Equation (1) below [38].

$$S = \frac{5\lambda}{8\sin\theta} \tag{1}$$

where *S* denotes the polymer chain separation, *λ* is the wavelength of the X-ray that was used, and *θ* is the angle of diffraction at the amorphous halo's maximum intensity. The average separation of the polymer chains was found to be 1.4 Å in the case of PPy. The Debye–Scherrer Equation (2) [39] was used to calculate the average crystallite size of PPy.

$$D = \frac{k\lambda}{\beta cos\theta} \tag{2}$$

**Figure 5.** (**a**) XRD peaks of neat polypyrrole and its composites with gum arabic. (**b**) TGA of neat polypyrrole and its composites with gum arabic.

*D* stands for the average crystallite size, while *k* stands for the dimensionless shape factor, which has a value of 0.9, which is close to unity. It varies depending upon the crystallite's shape, *λ* is the wavelength of X-ray that was used, and *β* is the angle of diffraction at full width and at half maximum. PPy has a crystallite size of 0.627 nm. Peaks were found at 2θ = 23.82◦, 25.97◦, 27.57◦, 30.41◦, and 34.99◦ in the PPy/GA 1 composite as shown in Figure 5a. The PPy/GA composites are partially amorphous and also partially crystalline in nature. The sharp and narrow peaks show the crystalline nature of the composites, whereas the halo and broad peaks show the amorphous nature of the composites. According to the previous discussion, increasing the quantity of GA in the composites to PPy/GA 2, where

the amount of GA is 0.25 percent, enhances the crystallinity of PPy [40]. By further increasing the amount of GA in the composite materials, the composites become less crystalline at PPy/GA 5. GA is mostly amorphous in nature. The crystallinity of PPy/GA 1 increases due to the formation of composites of GA with PPy, which is not an unexpected result. However, at higher concentration of GA in the composites (PPy/GA 5) the amorphous nature becomes dominant as clearly seen in Figure 5a, which is attributed to the mostly amorphous nature of GA.
