ABSTRACT
This study aims to prepare Ag-CuO nanoparticles and assess their efficiency in protecting the copper substrate. The prepared Ag-CuO nanoparticle was characterized using, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope/energy-dispersive X-ray (SEM/EDX), and transmission electron microscope (TEM). The anticorrosion performance of the epoxy coatings containing various weight percentages of Ag-CuO nanoparticles was evaluated in 3.5 wt% NaCl solution using potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques. The results showed that corrosion potential shifted from - 0.211 V for uncoated copper to - 0.120 V for 5.0 wt% Ag-CuO/epoxy hybrid nanocomposite. Electrochemical measurements indicated that the coating 5.0 wt% coating exhibited excellent inhibiting properties with an efficiency of 99.9%. Wettability and mechanical properties were measured for both uncoated and coated copper substrates. The contact angle for 5.0 wt% coating is equal to 104° enhancing the hydrophobic character of the surface. The study clearly establishes that the hybrid composite has a significant potential for protecting the copper substrate.
ABSTRACT
Polyaniline/nanocarbon (PANI/NC) nanocomposites have been prepared by in situ polymerization of aniline monomer in the presence of a stable colloidal solution of nanocarbon NC using ammonium persulfate as an initiator and silver ions (Ag+) as oxidizing agents to produce PANI/NC and PANI/NC/Ag2O nanocomposites, respectively. The morphological studies of the formed nanocomposites have been elucidated via transmission and scanning electron microscopes (TEM and SEM). Further characterization of the prepared nanocomposites has been done via infrared spectroscopy (IR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), particle size distribution analysis (PSD), fluorescence microscope (FM), UV-VIS spectroscopy, and finally surface analysis. XRD results confirmed the presence of silver oxide Ag2O nanoparticles, and the obtained data is well matched with the JCPDS card number 76-1393 of silver oxide. XPS analyses have shown two prevailing characteristic peaks for Ag 3d5/2 and Ag 3d3/2 at 367.1 and 373 eV, respectively, representing Ag2O nanoparticles, which are matchable with the XRD analysis. The PSD analysis revealed that the sizes of the prepared nanocomposites are in the size range from 60 to 140 nm. The FM measurements showed luminescence from the prepared nanocomposites upon irradiation with different lights. This recommends that the fluorophores present in the prepared nanocomposites have the potential to both absorb and emit light. The AC conductivity and the dielectric permittivity of the obtained nanocomposites at room temperature and at different frequency ranges have been investigated. At higher frequency ranges, the maximum ac conductivity obtained was 1.06 × 10-2 and 2.5 × 10-2 S.Cm-1 for the PANI/NC and PANI/NC/Ag2O, respectively. As far as we know, these new nanocomposites with superior optical and electrical characteristics have not been described yet in the literature.
ABSTRACT
In the current work, rice straw nanofibers (RSNF) with the width of elementary fibrils (~ 4-5 nm) were isolated from rice straw. The isolated nanofibers were used with zinc oxide nanoparticles (ZnONPs) to prepare flexible nanopaper films. Tensile strength and electrical properties of the prepared RSNF/ZnONPs nanopaper were investigated. The addition of ZnONPs to RSNF nanopaper did not deteriorate its mechanical properties and showed a slight improvement in tensile strength and Young's modulus of about 14% and 10%, respectively, upon the addition of 5% of ZnONPs. Microscopy investigation using scanning electron microscopy (SEM) showed the inclusion of the ZnONPs within the RSNF. Electrical conductivity and dielectric properties as a function of frequency at different temperatures were studied. The ac-electrical conductivity increased with frequency and fitted with the power law equation. The dc- electrical conductivity of the samples verified the Arrhenius equation and the activation energies varied in the range from 0.9 to 0.42 eV. The dielectric constant decreased with increasing frequency and increased with increasing temperature, probably due to the free movement of dipole molecular chains within the RSNF nanopaper. The high values of the dielectric constant and conductivity of the prepared nanopaper films support their use in electronic components.
