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Fabrication of ultra-thin, hydrophobic and flexible electromagnetic wave absorber sheets based on nano-carbon/carbonyl iron in a polypyrrole/silicone rubber matrix
摘要： In this work, electromagnetic (EM) wave absorbing properties of polypyrrole/silicone rubber (PP-SI) filled nano-carbon and carbonyl iron (CI) nanocomposites have been investigated in the X-band. The PP-SR matrix was provided by the incorporation of polypyrrole and liquid silicone rubber in the ratio of 10:90. The PP-SR serves not only as a matrix but also promotes the flexibility and EM wave absorption of the nanocomposite sheets. In the present research, the chemical, morphology, thermal, wetting, absorption, and mechanical properties of the EM wave absorber sheets are investigated. The EM wave absorber sheet with 3 wt% nano-carbon and 37 wt% CI and a thickness of 1 mm, exhibits a minimum reflection loss around ?13 dB at 10.27 GHz. The absorber sheet with an elongation of 520% could be qualified as a superior elastic sheet. The specimen represents higher thermal stability compared with pure SR, and the contact angle of the sheet proved that their surface should be hydrophobic.
关键词： Flexible wave absorbers,Silicone rubber,Polypyrrole,EM wave absorber sheets
更新于2025-09-23 15:21:21
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PEGylated polyethylenimine-stabilized polypyrrole nanoparticles loaded with DOX for chemo-photothermal therapy of cancer cells
摘要： Combination of kinds of therapy modalities is promising for effective cancer treatment. Herein, a kind of multifunctional nanoparticles (NPs) was developed for cancer chemo-photothermal therapy applications. Polypyrrole (PPy) NPs were formed using a facile polymerization method using poly(ethyleneimine) (PEI) as stabilizer, followed by polyethylene glycol (PEG) modification and anticancer drug doxorubicin (DOX) loading. Showing obvious absorbance in the NIR range, the obtained PPy-PEI-PEG NPs displayed well photothermal ability with desirable photothermal stability. The release of the loaded DOX can be promoted by pH and laser stimulation. Compared with single therapy modality, the combination of chemotherapy and photothermal therapy showed higher cancer cell killing effect. The cellular internalization of the obtained NPs was proved to be effective. The developed multifunctional NPs are promising candidates for combined therapy of cancer cells.
关键词： Polypyrrole nanoparticles,Polyethylenimine,Nanomedicine,Photothermal therapy,Chemotherapy
更新于2025-09-23 15:21:21
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Hydrothermal synthesis of quantum dots dispersed on conjugated polymer as an efficient electrodes for highly stable hybrid supercapacitors
摘要： Hydrothermal synthesis of graphene quantum dots (GQDs) composited with conjugated polymer were investigated the high specific capacitance and cyclic stability of supercapacitor. The situ chemical polymerization method was employed to synthesize the polypyrrole - graphene quantum dots (PPY-GQDs) composite at different concentrations of GQDs. The size, morphology and structural phase of the PPY- GQDs composites was studied by using Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FESEM), Atomic Force Microscope (AFM) and X-ray diffractometry (XRD) techniques respectively. The optical and electrochemical measurements were carried out by using Ultraviolet-Visible (UV–Vis) Absorption spectroscopy, Photoluminescence Spectroscopy (PL) and electrochemical work station. The cyclic voltammetry (CV) results show enhanced current density and area of CV loop with increasing scan rate and the concentration of GQDs. The Supercapacitor was fabricated by two electrodes owns a high energy density 67.8 Wh/kg and 93 Wh/kg at a power density of 1210 W/kg and 1430 W/kg for PGC1 and PGC3 composites. The highest specific capacitance values 467.32 and 647.54F/g are achieved by PGC1 and PGC3 composite compare to pure PPY. The PPY-GQDs composites achieved excellent cycle stability until the 2000 cycle. Thus, it demonstrates that GQDs is playing a unique and important role in improving the performance of a hybrid supercapacitor device.
关键词： Electrochemical Impedance spectra,Graphene quantum dots,Specific capacitance,Supercapacitors,Polypyrrole
更新于2025-09-23 15:21:01
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Synthesis and Characterization ofBaTiO3/Polypyrrole Composites with Exceptional Dielectric Behaviour
摘要： Higher concentrations of ceramic fillers induce brittleness in the ceramic/polymer hybrids which restrict their applications to limited fields especially when such hybrids are prepared for their use as dielectrics. We have synthesized and characterized different BaTiO3-polypyrrole (PPy) composites by changing the concentration of BaTiO3 from 1% by weight of PPy taken to 5 wt % to explore its effect on the dielectric parameters of the final product and found that the BaTiO3-polypyrrole composite with weight ratio of 0.05:1 exhibited highest dielectric constant, lowest dielectric loss and thermally most stable. All the composites were prepared using in-situ polymerization of pyrrole in an aqueous dispersion of low content of BaTiO3 in the presence of small amount of Hydrochloric acid. These composites were characterized for their microstructure and crystallinity by X-ray diffractometer (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) while thermal stability by thermo gravimetric (TGA) analysis. An impedance analyser (LCR meter) was utilized to investigate the dielectric parameters. FT-IR data confirmed the presence of the two phases and their interaction, inferred from the shifting of normal PPy peaks. The data obtained from XRD confirmed the presence of crystallites of 2.8 to 5 nm with dominant crystallinity of the filler, TGA analysis (25 to 600 ?C) confirmed the higher thermal stability induced on successive addition of the filler into the prepared composites as compared to that of pure PPy in a wide temperature range which is unusual for such a low % age addition of the filler. The SEM analysis together with XRD results reveal that the successive introduction of BaTiO3 particles produced crystallites of 2 to 5 nm size which bonded together and changed the hemispherical shaped larger grains of the matrix to regular shaped smaller grains. The dielectric constant of the composites was enhanced with filler contents from 178 to 522 at 1 MHz for 1 wt % and 5 wt % BaTiO3 respectively. It was concluded that the introduction of BaTiO3 into the polymer matrix with this new procedure has greatly affected the polymerization process, thermal stability, morphology and dielectric properties of the host matrix and has resulted in a novel series of the composites which may have broad applications.
关键词： barium titanate,polymerization,dielectric behaviour,polypyrrole
更新于2025-09-23 15:21:01
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A ternary nanocomposites of graphene / TiO <sub/>2</sub> / polypyrrole for energy storage applications
摘要： Designing a new electrode active materials including graphene and nanomaterials such as Titanium dioxide (TiO2) with polypyrrole have important for supercapacitor devices. In this work, we present a new ternary nanocomposite for using reduced graphene oxide (rGO), TiO2 and polypyrrole (rGO/TiO2/PPy) for supercapacitors. rGO/TiO2/PPy nanocomposites were characterized by the analysis of Fourier transform infrared-attenuated transmission reflectance (FTIR-ATR), Raman spectroscopy, and scanning electron microscopy-energy dispersion X-ray analysis (SEM-EDX). Electrochemical tests were taken by galvanostatic charge/discharge (GCD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies. We have obtained the highest specific capacitance of Csp D 431.23 F/g for [rGO]o/[Py]o D 1/1 at 10 mV/s. A ternary rGO/TiO2/PPy nanocomposite has higher Csp values than Csp D 122.12 F/g at 10 mV/s for rGO/PPy, Csp D 93.17 F/g at 4 mV/s for rGO and Csp D 45.16 F/g at 4 mV/s for GO. A high energy density was obtained as E D 2.03 Wh/kg and power density of P D 18.3 kW/kg for rGO/TiO2/PPy nanocomposite at 1000 mV/s. rGO/TiO2/PPy nanocomposite had a relatively high Coulombic efficiency, as well as a retention of ?100% of its original capacitance for [rGO]o/[Py]o D 1/1 after 1000 cycles. A novel synthesized rGO/TiO2/PPy nanocomposite may be used for supercapacitor devices due to its good electrochemical performances.
关键词： energy density,reduced graphene oxide,circuit model,TiO2,supercapacitor,polypyrrole
更新于2025-09-23 15:19:57
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Study of optical and electrical property of NaI-doped PPy thin film with excellent photocatalytic property at visible light
摘要： Conductive polymers perform as a new class of very active photocatalysts under visible light. Among them, polypyrrole (PPy) is one of the most promising conjugated polymers with a wide range of applications. PPy and doped PPy were synthesized on glass plate in thin film form by a facile simple successive ionic layer adsorption and reaction method. Polypyrrole is doped with dodecyl benzene sulphonic acid, toluene sulphonic acid, hydrochloric acid, sodium iodide (NaI), citric acid (commercial) and citric acid (lemon). The synthesized thin film was well characterized using UV–visible spectrophotometer, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and photoluminescence (PL). The electrical conductivity was measured by Hall effect measurements. Among various organic and inorganic acid dopants, NaI-doped PPy thin film exhibited narrow band gap and has excellent ability to absorb light in red region of the spectrum. NaI-doped PPy thin film showed higher conductivity when compared to other dopants. A lower PL intensity of NaI-PPy thin film indicates higher electron–hole pair separation efficiency. The photocatalytic activities of PPy thin film and NaI-doped PPy thin film on rhodamine 6G dye under visible light were systematically investigated. NaI-doped PPy thin film had better degradation efficiency than PPy due to its higher electron–hole pair separation efficiency.
关键词： Dye degradation,Polypyrrole,Rhodamine 6G,Thin film
更新于2025-09-19 17:15:36
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Solvent-free and large-scale preparation of silver@polypyrrole core@shell nanocomposites; structural properties and terahertz spectroscopic studies
摘要： There is a growing interest over the environmental safety and mass-production of polymer nanocomposites. Solvent-free synthetic pathways are considered as promising alternative green techniques because of their high efficiency, simplicity and negligible liberation of hazardous waste. A new synthetic route has been developed to synthesize silver@polypyrrole core@shell nanocomposites at ambient condition. The silver nanoparticles are directly synthesized via solid-state reaction with poly(vinylpyrrolidone) and then pyrrole is polymerized in Ag/PVP powder. The band gap value decreases with the increased addition of pyrrole in the preparation step due to the formation of more silver nanoparticles. Scanning and transmission electron microscope confirm the formation of core@shell structure. The negatively charged carbonyl group of poly(vinylpyrrolidone) can bind to polycationic polypyrrole by an electrostatic effect to form the core@shell structure. The terahertz spectroscopy characterizes the prepared core@shell nanocomposites that are well fit to the Drude-Smith model. The DC optical conductivity in the terahertz range (0.3–2 THz) is increased with increasing Py addition.
关键词： Core@shell,Solvent-free method,Silver,Polypyrrole,Optical conductivity
更新于2025-09-19 17:13:59
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The fabrication of graphene-polypyrrole composite for application with dye-sensitized solar cells
摘要： This research is to study the preparation of graphene-monodispersed polypyrrole composite materials for uses as a counter electrode in dye-sensitized solar cells (DSSCs). The preparation started with the synthesis of graphene oxide (GO), followed by the preparation of composite films by polymerization method and the GO reduction process by ascorbic acid. The characterizations included thermal-gravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR), raman spectroscopy, X-ray diffraction (XRD), field-emission electron microscopy (FESEM) and cyclic voltammetry (CV). The DSSCs’ efficiency tests were also conducted and analyzed. Based on the test results, it was found that DSSCs prepared from PPy/RGO-5 composite films with 5% by weight of reduced graphene oxide (RGO) could give an optimal efficiency. Nevertheless, the efficiency of such solar cells was much less than that of DSSCs with platinum counter electrode. This could be due to incomplete reduction of graphene oxide, resulting low electron transfer ability and electrocatalytic activity toward the reduction of electrolyte solution.
关键词： Reduced graphene oxide,Polypyrrole,Dye-sensitized solar cells,Counter electrode
更新于2025-09-16 10:30:52
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Controlled fabrication of gold nanobipyramids/polypyrrole for shell-isolated nanoparticle-enhanced Raman spectroscopy to detect γ-aminobutyric acid
摘要： Shell-isolated nanoparticle-enhanced Raman Spectroscopy (SHINERS) has been a non-destructive, highly sensitive, specific and powerful sensing method. Detection of γ-aminobutyric acid (GABA) and glutamate, main neurotransmitters in the human brain, is important to diagnosis the neurological disorder. The purpose of this study is preparing a simple, rapid and inexpensive fabrication of Au nanobipyramids/polymer core/shell as a SHINERS-based biosensor to detect different neurotransmitters such as GABA and glutamate with high sensitivity and specificity. Au nanobipyramids/polymer core/shell was fabricated by using two steps process. In the first Au nanobipyramids with longitude and latitude axial of about 100 nm and 10 nm, respectively, was prepared based on the chemical reduction of Au ions by using sodium borohydride as a reducing agent. Then a thin layer of polypyrrole was used for decorating the Au nanobipyramids by using direct polymerization in the presence of Au nanobipyramids. The sensor composed Au nanobipyramids with a thin layer of polypyrrole that could measure GABA within a wide range of concentrations in the presence of human serum. And this sensor was used for direct monitoring of GABA and glutamate. The proposed biosensor can be applied to monitor the level of neurotransmitters accurately for the diagnosis of various neurological disorders with optical signal enhancement.
关键词： Glutamate,Polypyrrole,Gold nanobipyramids,γ-Aminobutyric acid,Shell-isolated nanoparticle-enhanced Raman spectroscopy
更新于2025-09-12 10:27:22
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Effect of conductive polymers on the optical properties of electrospun polyacrylonitryle nanofibers filled by polypyrrole, polythiophene and polyaniline
摘要： The aim of the study was the production of composite nanofibers using the electrospinning methods from a PAN/DMF solutions with PANI, PPy and PT conducting polymers. A scanning electron microscope (SEM) was used in order to carry out an analysis of the morphology a of the resulting nanowires. In order to examine the chemical structure of the composite nanofibers, energy dispersive spectrometry (EDX) and Fourier-Transform Infrared spectroscopy (FTIR) were used. The analysis of the optical properties and the energy band gap of the prepared nanowires was determined by spectral analysis using a UV-Vis spectrophotometer. Using the recorded absorbance spectra determined the banded refractive index n, real n' and imaginary k part of the refractive index as a function of the wavelength, complex dielectric constant ?, real and imaginary part ?r and ?i of the dielectric constant as a function of the wavelength of the obtained nanofibers. The obtained results, which were as follows: energy band gap of 3.77 – 4.08 eV, complex refractive index coefficient values of 1.61 – 2.98 and dielectric constant in the range of 2.58 – 8.87, suggest the possibility to applied of the produced nanomaterials in photovoltaic devices.
关键词： optical properties,polythiophene,polypyrrole,polyacrylonitryle,polyaniline,nanofibers
更新于2025-09-12 10:27:22