Novel conductive polypyrrole/zinc oxide/chitosan bionanocomposite: synthesis, characterization, antioxidant, and antibacterial activities

Figures & data

Figure 1 Schematic illustration of the synthesized polypyrrole/zinc oxide (ZnO)/chitosan bionanocomposite film at the surface of the electrode.

Figure 2 Fourier transform infrared spectra for zinc oxide nanopowder, deposited film of Ppy/CS composite, and Ppy/ZnO/CS composite film.

Note: Arrows show the position of characteristic peaks.

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide.

Figure 3 X-ray diffraction patterns of (A) pure Ppy/CS, (B) Ppy/ZnO/CS 5%, (C) Ppy/ZnO/CS 10% composite films, and (D) ZnO nanopowder.

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide.

Table 1 Characteristics of the investigated Ppy/ZnO/CS bionanocomposites

Sample	ZnO nanoparticles content (wt%)	Conductivity (S·cm^−1)	Thickness (mm)
Ppy/CS	0.0	62.36	0.10
Ppy/ZnO/CS	5.0	33.55	0.98
Ppy/ZnO/CS	10	54.64	0.10
Ppy/ZnO/CS	15	56.95	0.10
Ppy/ZnO/CS	20	61.15	0.99

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide; wt, weight.

Figure 4 Thermogravimetric curves of (A) Ppy/CS composite, (B) Ppy/CS composite with 10%, (C) 15%, and (D) 20% ZnO nanoparticles.

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide.

Figure 5 Mechanical properties of the Ppy/CS nanocomposite.

Notes: (A) Storage modulus (E’) versus ZnO NP content and (B) storage modulus (E’) versus temperature for (a) Ppy and Ppy/CS films prepared with (b) 0.0%, (c) 5.0%, (d) 10%, and (e) 15% of ZnO NPs.

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide; NP, nanoparticle; wt, weight.

Figure 6 Scanning electron microscopy images and energy-dispersive X-ray fluorescence spectra of (A, D) Ppy, (B, E) Ppy/CS, and (C, F) Ppy/ZnO/CS (20 wt%).

Abbreviations: Ppy, polypyrrole; CPS, counts per second; CS, chitosan; wt, weight; ZnO, zinc oxide.

Table 2 Average inhibition zone for Ppy/ZnO/CS bionanocomposites with different content of ZnO nanoparticles

Bacteria		Inhibition zone (mm)				Control positive (mm)
		Ppy/ZnO/CS (5%)	Ppy/ZnO/CS (10%)	Ppy/ZnO/CS (15%)	Ppy/ZnO/CS (20%)	SM
Gram-positive	Staphylococcus aureus	9.02±0.061	14.53±0.030	18.36±0.010	28.63±0.010	21.2±0.020
	Bacillus cereus	15.62±0.078	18.26±0.061	19.18±0.030	20.83±0.017	21.2±0.058
Gram-negative	Pseudomonas aeruginosa	20.54±0.141	23.85±0.034	25.42±0.046	29.60±0.010	29.1±0.045
	Escherichia coli	9.00±0.043	11.89±1.076	15.30±0.0173	17.70±0.026	21.2±0.028

Note: Data shown are mean ± standard deviation.

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide; SM, streptomycin.

Figure 7 The antibacterial activity of Ppy/ZnO/CS bionanocomposite with 5% ZnO nanoparticle content evaluated by well diffusion method against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus bacteria (the test repeated three times for each sample).

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide.

Table 3 Time-dependent antioxidant activity of the Ppy/ZnO/CS bionanocomposite with different content of ZnO nanoparticles

Time (min)	DPPH inhibition (%)
	Ppy/CS	Ppy/ZnO/CS (5%)	Ppy/ZnO/CS (10%)	Ppy/ZnO/CS (15%)	Ppy/ZnO/CS (20%)
0	52.597±0.34	74.814±0.22	76.603±0.12	77.582±0.22	79.169±0.32
10	52.599±0.16	75.624±0.27	78.191±0.32	79.001±0.42	80.283±0.22
20	54.726±0.51	76.468±0.63	78.359±0.21	79.574±0.38	80.452±0.38
30	54.827±0.33	78.461±0.33	78.764±0.21	80.249±0.40	80.722±0.31
40	55.379±0.45	78.933±0.43	80.317±0.35	80.351±0.25	80.959±0.40
50	55.604±0.12	79.574±0.22	80.453±0.27	80.621±0.27	81.127±0.34
60	56.110±0.35	80.553±0.36	80.689±0.29	81.499±0.33	82.309±0.30
70	56.178±0.24	81.161±0.38	81.769±0.37	82.376±0.52	82.984±0.33
80	56.988±0.28	81.836±0.41	82.073±0.22	82.478±0.31	83.389±0.29
90	58.541±0.51	82.174±0.27	83.355±0.41	83.491±0.36	83.693±0.22
100	58.912±0.33	84.065±0.23	83.794±0.19	83.558±0.22	84.166±0.43

Note: Data shown are mean ± standard deviation.

Abbreviations: Ppy, polypyrrole; CS, chitosan; ZnO, zinc oxide; DPPH, 2,2-diphenyl-1-picrylhydrazyl; min, minutes.