Electrical, thermal, morphological, and antibacterial studies of synthesized polyaniline/zinc oxide nanocomposites

Polyaniline/zinc oxide nanocomposites (PANI/ZnO NCs) have been synthesized by chemical oxidative polymerization of aniline in a dispersion containing different weight content of ZnO nanoparticles (NPs) (1.5, 3, 5, and 8 wt% to aniline). ZnO NPs were prepared by combustion method. The structural, morphological, thermal properties of the synthesized PANI/ZnO NCs were evaluated using various analytical tools such as FTIR, TEM, SEM, TGA, and XRD. The variation of electrical conductivity and permittivity of the synthesized NCs with frequency was studied. The antibacterial activities of the NCs to Escherichia coli and Staphylococcus aureus were evaluated. FTIR data of the NCs proved the formation of H-bonding between ZnO and –NH of PANI. XRD pattern of ZnO showed hexagonal wurtzite crystalline structure of particle size 46.67 nm, while the addition of ZnO NPs to poorly crystalline PANI indicated nearly the same crystalline structure. TEM of ZnO NPs showed hexagonal and pseudospherical crystalline structure, while that of PANI/ZnO NCs revealed ZnO NPs were coated in PANI matrix. SEM images displayed uniformly dispersed ZnO NPs in PANI matrix with minute agglomerated particles. Medium antibacterial activity to E. coli was obtained for all NCs, while that containing 8% ZnO revealed high activity to Staphylococcus aureus. The variation of conductivity of the NCs with frequency at room temperature showed that ZnO plays an important role in conduction mechanism such that different phases were obtained. NC containing 5% ZnO possessed the highest conductivity. The permittivity of NCs decreased with the frequency and increased with increasing temperature. The dielectric loss decreased with the frequency indicating energy conservation.