الفهرس | Only 14 pages are availabe for public view |
Abstract The present work was devoted to investigate the development of stabilized and densely dispersed chitosan-silver hybrid nanoparticles (CS-Ag NPs) using a new eco-friendly “green” approach based on electrochemical oxidation/complexation process followed by UV irradiation reduction. The synthesized CS-Ag NPs were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), elemental analysis, atomic absorption, energy dispersive X-ray (EDX), Fourier transform infrared (FTIR), differential thermogravimetric analysis (DTGA, DSC), zeta potential (ZP) and UV–Vis spectroscopy. These characterizations were carried out to specify the functional groups, crystalline structure, average size and size distribution, surface charge and surface plasmon resonance of the developed CS-Ag NPs. Formation of the CS-Ag NPs was confirmed from the appearance of surface plasmon absorption maxima around 420 nm in the UV-Vis spectra. The obtained CS-Ag NPs were uniform and spherical with average size in the range of 2 to 34 nm. The CS-Ag NPs synthesized in the present study also demonstrated a relatively strong antibacterial activity against Gram-positive (B. thuringiensis) and Gram-negative (P. aeruginosa) bacteria as compared to that of control (CS) by using the nutrient agar disc diffusion method with determination of the inhibition zones (mm). This antibacterial activity increased with increasing the concentration of the CS-Ag NPs. The obtained results revealed that the CS-Ag NPs developed in this study could be useful in various biological and biomedical applications, such as surgical devices and drug delivery vehicles. Dielectric studies a powerful scientific technique in the interpretation of the effect of dative bond on the dielectric properties. The frequency dependence part of dielectric parameters (dielectric constant, dissipation factor and real part of electric modulus) is non-Debye type. The temperature dependence part of dielectric parameters is a very usefully representated in the glass transition temperature determination. The dielectric spectra of the investigated samples showed that the dielectric constant decreases with increasing frequency. The relaxation time and its associated activation energy were also determined from the loss factor spectra. |