*3.2. Phase Analysis*

The XRD patterns of PCL mat and PCL/TiO2 coatings with 2, 5 and 7 wt % of TiO2 content is shown in Figure 2a along with electrosprayed TiO2 nanoparticles for reference. PCL is a semi-crystalline polymer, which can be spotted by two characteristic peaks in the region of 20◦–25◦ (2θ = 22.1◦ and 24.5◦). The TiO2 anatase nanoparticles exhibit characteristic peaks at 2θ values of 25.6◦, 35.9◦, 37.9◦, 38.9◦, 48.4◦, 53.9◦ and 56.1◦, corresponding to the diffraction patterns of (101), (103), (004), (112), (200), (105), and (211) crystalline planes respectively (JCPDS data No. 36–1451). From the Figure 2a, it can be noted that the relative intensities of TiO2 are increased with increasing TiO2 content. Also, incorporation of TiO2 nanoparticles into the PCL fibrous structure resulted in the widening of peak widths and reduction in its peak height implying the decrease in the crystallinity of PCL structure.

FTIR spectra of the PCL/TiO2 coatings with 2, 5 and 7 wt % of TiO2 content and pure PCL mat for comparison are shown in Figure 2b. The analysis shows the presence of H-bonds between organic (PCL) and inorganic (TiO2) components of the hybrid materials. The spectrum of the TiO2 coatings are visible at wavenumber lower than 998 cm−<sup>1</sup> are due to Ti-O and Ti-O-Ti vibration bands in the lattice [36]. The peaks located at 1725 cm<sup>−</sup>1, 1182 cm−1, 1054 cm−1, and 2865 cm−<sup>1</sup> corresponds to carbonyl groups of C=O, C–O–C, C–O, and alkyl group of C=H stretching vibrations of PCL polymer respectively. The bands present at 564–647 cm−<sup>1</sup> (PO4 <sup>3</sup><sup>−</sup> bending vibration), 878 cm−<sup>1</sup> (P–OH stretching) and 999–1102 cm−<sup>1</sup> (PO4 <sup>3</sup><sup>−</sup> asymmetric stretching) [37]. Most corresponding bands of TiO2 were detected in the PCL/TiO2 spectrum recommends that TiO2 is effectively incorporated into the PCL nanofibrous mat to form nanocomposites. The reduced intensities of PCL in PCL-TiO2 nanocomposites is because of the presence of physical interaction between PCL and TiO2 nanoparticles [38].

**Figure 2.** (**a**) XRD and (**b**) FTIR patterns of PCL/TiO2 (2, 5 and 7 wt %) nanocomposites in comparison with pure PCL.
