Papers by Keyword: Polyaniline (PANI)

Abstract: Conducting core–shell latex nanoparticles were synthesized by coating near–monodisperse, nanometer sized water–based polyurethane (PU) latex nanoparticles through in situ chemical polymerization of aniline. These latex nanoparticles showed nearly spherical shape and relatively narrow particle size distribution. It is found that good core–shell structure of latex nanoparticles could be well formed due to the interaction between the carboxyl groups of PU and imine groups of polyaniline (PANI), and the conductivity of the composite films can be controlled through adjusting the weight ratio of aniline monomer and PU latex.

Abstract: Semi-interpenetrating polymer network of coal/polyaniline (PANI) composite material were prepared by in situ polymerization. Raw coal was oxidized in different conditions by H₂O₂ and HNO₃, respectively. The total acidic groups analysis, Fourier transform infrared (FTIR) spectrum, and conductivity test of the raw coal and the oxidized coal/PANI composite material were conducted. The results showed that the increases of the carboxyl groups and the hydroxyl groups were mainly attributed to the hydrolysis of the weak ether link and the transform from the carboxylate to carboxylic acid. These increases were benefit to the reaction of coal and PANI, and consequently enhanced the conductivity of the composite material. The maximum conductivity of oxidized coal/PANI reached 4.72×10^‑1 S/cm.

Abstract: Different kinds of dopants were selected to dope polyaniline by chemical oxidative polymerization in this paper. Major characteristic peaks and microstructure of the doped polyaniline were analyzed by Fourier transform infrared spectra (FTIR) and scanning electron microscope (SEM). Measurement of membrane potential indicated that polyaniline doped with protonic acid such as sulfosalicylic acid (SSA) and hydrochloric acid (HCl) had characteristic of anionic selectivity, and polyaniline doped with cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) had characteristic of cationic selectivity. Doped polyaniline was added to the epoxy resin to obtain different ions selective coatings, such as anionic coating, cationic coating and bipolar coating. Results of electrochemical test in 5% potassium chloride (KCl) solution (at 60 °C) showed that anti-corrosion performance of the bipolar coating is better than that of cationic coating, and performance of the cationic coating is better than that of anionic coating. And the coatings contained HCl-doped polyaniline had better protection performance than those of SSA-doped because of its micro appearance and distribution.

Abstract: Nanocomposite based on polyaniline (PANI) and α-zirconium phosphate (α-ZrP) has been synthesized by in situ polymerization using aniline intercalation compound (ANI)/ZrP as intermediate. Aniline was successfully intercalated into the interlayer spacing of crystalline α-ZrP forming a double-phase intermediate by adsorption. The intercalated aniline was polymerized by adding appropriate amount of ammonium peroxodisulphate (APS) solution. The synthesized nanocomposites were characterized by XRD, SEM, and FT-IR. X-ray diffraction patterns showed that PANI was formed outside α-ZrP. TGA/DSC analysis showed improved thermal stability for the PANI/ZrP nanocomposite in comparison with pure PANI. The PANI/ZrP nanocomposite was studied by cyclic voltammetry (CV), which revealed good redox activity and electrochemical-cycling stability in acidic solution. The interaction between PANI and nanosheets greatly affected the electrochemical behavior of PANI/ZrP nanocomposite. The electrochemical behavior of PANI/ZrP nanocomposite in HCl solution with different pH values has been studied in detail.

Abstract: The polyaniline(PANI)-poly(vinyl alcoho1)(PVA) composite film doped with HC1 was prepared with PVA as matrix. Effects of PVA content, film drying temperature on properties of PANI-PVA composite film were studied. Tensile strength, elasticity, conductivity and thermal stability of PVA, HC1-PANI or PANI-PVA were compared. Tensile strength and elasticity of PVA film were the largest, its conductivity was the least. The conductivity of PANI-PVA was the largest, tensile strength and elasticity of PANI-PVA are bigger than those of HC1-PANI. The order of their thermal stability is PVA> HC1-PANI > PANI-PVA before 260°C, the order of their thermal stability is HC1-PANI>PANI-PVA> PVA after 260°C.

Abstract: In this paper, we have successfully synthesized polyaniline nanotubes by using chemical oxidation polymerization. This synthesis is simple and an effective way to prepare one-dimensional polymer nanotubes. By transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectrum (FTIR), the morphology and physical structures of the as-prepared products were characterized. By cyclic voltammetry we studied the electrocatalytic activity of polyaniline nanotube modified glassy carbon electrode on ascorbic acid. The results show that the polyaniline nanotube modified electrode has excellent electrocatalytic activity on ascorbic acid. Compared with those of the bare glassy carbon electrode, the anodic peak potential of ascorbic acid shifts negatively 0.212 V on the modified electrode, and the anodic peak current increases 43 %. And the concentration of ascorbic acid shows a good linear relation at the range of 1.0×10^-5 ~ 0.1 M with the minimum detection limit of 1.0 × 10^-6 M.

Abstract: Polyaniline (PAni) film was successfully electrodeposited on the surface of steel substrates in oxalic acid electrolyte by cyclic voltammetry at different potential sweep rates (dE/dt) (10, 20 and 30 mVs-1) and different pH values (1.55, 2.55 and 3.55). The coated steel with PAni was characterized by Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. The corrosion resistance of the electrodeposited layers was evaluated by potentiodynamic polarization in 0.1 M NaCl aqueous solution. The results showed that with increasing pH and sweep rate the amount of corrosion rate decreased and increased respectively. Moreover, the correlation between variation of anodic charge (Qa) with pH and sweep rate has been evaluated. The variation of anodic charge confirmed that the growing rate of polymer decreased with increasing sweep rate and pH. The result of potentiodynamic polarization showed that the coated steel with synthesized PAni in pH 3.5 and sweep rate 0.01Vs-1 had better protective properties against corrosion.

Abstract: In order to improve the sensing-properties of carbon nanotube based composite for potential applications in chemical sensors, CNTs/PANi core/shell-structured nanowires were prepared with in-situ polymerization approach. A series of characterizations was carried out by TEM (transmission electron microscopy), the Fourier-Transform Infrared (FTIR) spectra, and so on. A chemical prototype sensor was constructed based on CNTs/PANi core/shell-structured nanowires and interdigital-structured electrodes on flexible polymer substrate. The gas-sensing behaviors of the sensor to some gases operating at room temperature were examined. Results showed that the sensitivity of CNTs/PANi core/shell-structured nanowires was increased dramaticly compared with pure carbon nanotube materials. This provides a carbon nanotube based composite materials with enhanced gas-sensitivity, which would have potential applications in some chemical sensors.

Abstract: In the present work we have reported the effect of temperature on the gas sensing properties of pure Polyaniline (PANI) and Multiwall carbon nanotube (MWNT) doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and MWNT doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline using ammonium persulfate in an acidic medium. The thin sensing film of chemically synthesized PANI and MWNT doped PANI composite were deposited onto finger type Cu-interdigited electrodes using spin cast technique to prepared chemiresistor type gas sensor. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature, MWNT doped PANI composite sensor shows higher response value and sensitivity with good repeatability in comparison to pure PANI thin film sensor. It was also observed that both PANI and MWNT doped PANI composite thin film based sensors showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

Abstract: Cobalt oxide-Polyaniline (Co₃O₄/PANI) nanocomposites were prepared via inverted emulsion polymerization. The structure of the obtained composites were characterized by X-ray diffraction (XRD). The electrochemical behavior was studied by cyclic voltammetry(CV) and electrochemical impedance spectrometry(EIS) experiments. The Co₃O₄/PANI(1:2) composite calcined at 400°C exhibits the highest capacitance value of 357 F/g at the scan rate of 5mV/s.