Synthesis and characterization of highly stable and water dispersible hydrogel–copper nanocomposite

Highly stable and water dispersible hydrogel–copper nanocomposite was prepared in the present work. Copper ions were allowed to diffuse into the water-swollen hydrogel then reduced inside the hydrogel network with hydrazine. Formation of the hydrogel–copper nanocomposite was confirmed by X-ray diffraction (XRD) technique, UV–Vis and FTIR spectrophotometry, dynamic light scattering (DLS) and scanning electron microscopy (SEM). UV–Vis spectrum of the nanocomposite exhibited maximum absorption at ~ 562 nm, which was attributed to the surface plasmon resonance of copper nanoparticles. Height and position of the absorption maxima were dependent to pH during synthesis, because of the dependence of nanoparticles size to the pH. The ruby red color of the nanocomposite was remained unchanged up to three months. Colloidal aqueous solution of copper nanoparticles was obtained via ultrasound-assisted dispersion of nanocomposite in water. Cyclic voltammograms obtained on pencil graphite (PG) electrode modified with nanocomposite demonstrated that copper nanoparticles were more resistant against oxidation than bulk copper metal. Disk diffusion antibacterial test indicated that hydrogel–copper nanocomposite was effective growth inhibitor against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria.