Fabrication of transition-metal-doped polypyrrole/multiwalled carbon nanotubes nanocomposites for supercapacitor applications

Preparation and Electrochromic Properties of MnO2/PPy Composite Films with Coral-like Structures

MnO2/polypyrrole (PPy) composite films were deposited on fluorine-doped tin oxide (FTO) conductive glasses by a two-step wet-chemical method, including electrochemical deposition and chemical bath deposition (CBD). The porous MnO2 films were first grown on FTO glasses by an electrodeposition method. Second, polypyrrole nanoparticles were polymerized by the oxidation-reduction reaction between MnO2 and pyrrole, using the presynthesized MnO2 as the skeleton. Then, MnO2/PPy composite films with coral-like structures were obtained. The electrochemical and electrochromic (EC) properties of the prepared films were investigated. The results show that, compared to the single MnO2 or PPy film, the MnO2/PPy composite film has a larger optical modulation (67.3% at a wavelength of 900 nm), faster response times (4 s for coloration and 3 s for bleaching), and a higher coloration efficiency (218.16 cm2·C-1). The high coloration efficiency attests to the exceptional performance of the composite film in converting electrical signals into vivid color changes. The electrochemical stability test results show that the composite film maintains a stable EC performance after 200 coloration/bleaching cycles. The coral-like structures of the composite film are responsible for the better EC properties.

Development, Characterization and Valuable Use of Novel Dosimeter Film Based on PVA Polymer Doped Nitro Blue Tetrazolium Dye and AgNO3 for the Accurate Detection of Low X-ray Doses

Currently, the uncontrolled exposure of individuals to X-rays during medical examinations represents a substantial danger that threatens both medical professionals and patients. Therefore, radiation dosimetry for low X-ray doses is a very important control of radiation practice in medical diagnostic radiology. In line with this, the current study proposes a valuable dosimeter-based PVA thin film doubly doped with silver nitrate salt and nitro blue tetrazolium dye. The nanocomposite film was prepared via a simple casting method and the different processing parameters were optimized. The performance of radiation detection was evaluated according to optical, chromic, chemical and structural changes after exposure to variable low X-ray doses (0, 2, 4, 10 and 20 mGy). The different film labels exhibited an excellent stability behavior in dark and light upon 30 days of storage. The UV-Vis spectrophotometric study showed a gradual increase in the maximum absorbance as a function of the dose and the corresponding response curve confirmed this linear variation (R = 0.998). A clear structural modification was recorded via X-ray diffraction (XRD) analysis revealing the increase in crystallinity with the level of the dose received by the nanocomposite films. Microscopic surface analysis via SEM assessments revealed a significant morphological change in PVA/Ag⁺/NBT films exposed to increased radiation doses and typical dendrites growing in needle- or tree-like microstructures appeared with a high X-ray dose. Finally, the nanocomposite films before and after irradiation were evaluated via a spectrocolorimetric study and the different CIELab coordinates, the color difference, as well as the color strength, showed a linear correlation with the intensity of the applied dose. This new dosimeter design could, therefore, provide a promising and efficient alternative for prompt and accurate detection of low X-rays doses in diagnostic radiology.

The electropolymerization of N,N′-(propane-1,3-diyl)bis(2-aminobenzamide), characterization, and capacitor study

In this study, aniline-based monomer, N, N′-(propane-1,3-diyl)bis(2-aminobenzamide), (PAB), was synthesized and characterized by proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), and Fourier transform infrared spectroscopy. The electropolymerization of the monomer was performed on glassy carbon electrode by cyclic voltammetry (CV). The effects of solvent, dopant, scan number, and scan rate on the electropolymerization and properties of the poly(PAB) films were investigated. The modified electrode was also characterized by Fourier transform infrared-attenuated total reflection spectroscopy and scanning electron microscopy–energy-dispersive X-ray analysis. The capacitive properties of the poly(PAB) films were firstly tested by electrochemical impedance spectroscopy. The highest specific capacitances ( Csp) of poly(PAB) films were obtained as Csp = 6.22 mF cm−2 in 0.1 M lithium perchlorate/acetonitrile (ACN) for [PAB]0 = 20 mmol dm−3 and Csp = 16.9 mF cm−2 in 1 mol dm−3 sulfuric acid for [PAB]0 = 5 mmol dm−3 at the scan rate of 5 mV s−1 from CV measurements. This study is novel because it was the first study on capacitance performances of poly(PAB) films in the literature.

Capacitive performance of ruthenium-coordinated polypyrrole

Ruthenium coordinated polypyrrole is developed as an active electrode material for supercapacitors.

Investigation of a Branchlike MoO(3)/polypyrrole hybrid with enhanced electrochemical performance used as an electrode in supercapacitors

A branchlike MoO3/polypyrrole conductive nanocomposite was facilely prepared by wrapping a homogeneous polypyrrole (PPy) layer around MoO3 nanobelts via the in situ oxidative polymerization of a self-assembled pyrrole monomer. X-ray powder diffraction characterization demonstrated that the PPy polymer does not hinder the crystallization of the MoO3 nanobelts substrate. The electrochemical tests show that the specific capacitance of 129 F g(-1) for the MoO3/PPy hybrid is higher than both pristine MoO3 and pure PPy. Moreover, the hybrid electrode with good electrical conductivity displays good cyclic stability of 90% retention after 200 cycles of charge/discharge. These results indicate a promising potential application of the MoO3/PPy nanocomposite for use as an effective electrode material in supercapacitors.