Influence of structure of poly(o-phenylenediamine) on the doping ability and conducting property (original) (raw)
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Poly(o-phenylenediamine) (PoPD) was synthesized from o-phenylenediamine (oPD) using ammonium persulfate (APS) as an oxidizing agent in varying pH of reaction medium. The polymers were characterized by UV-VIS, 1HNMR and FTIR spectroscopy, thermogravimetric and elemental (CHNS) analyses. Solubility tests for the synthesized polymers were performed in various solvents and it was found that the polymer synthesized in lower pH medium was insoluble. The difference in their solubility is due to their structural difference, which can be supported by the proposed mechanisms of polymerizations. The spectral results clearly indicated that the ladder structure was formed in lower pH medium while open ring structure (with some ladder unit) or dimer was formed at higher pH. Fourprobe DC electrical conductivity of the synthesized polymers was also measured. The average DC conductivity of the polymer doped with hydrochloric acid was observed 8.8 x 10-5 S/cm for the synthesized open ring polymer while it was only 1.7 x 10-7 S/cm for the synthesized ladder polymer.
Chemistry and Chemical Technology, 2010
Emeraldin salt of polyaniline was synthesized by chemical oxidative polymerization method; this salt is soluble in common organic solvents. The obtained results are discussed with reference to lactic acid doped polyaniline. It has been observed that acrylic acid doped polyaniline is comparatively more soluble than polyaniline doped with lactic acid in common organic solvent such as m-cresol, NMP (N-methyl pyrrolidinone), DMSO, DMF, etc. The acrylic acid doped polymer prepared using lactic acid is comparatively more soluble in m-cresol and NMP than the polyaniline without acrylic acid. UV-Visible spectra for acrylic acid doped polyaniline reveals the coil conformation at higher wavelength along with sharp peak. This indicates that the conductivity of acrylic acid doped polyaniline is higher than that of polyaniline without acrylic acid. A broad and intense band at 3400-3300 cm-1 (N-H stretching) and 1120-1225 cm-1 accounts for higher degree of doping and protonation of amine and imine N-atom. These results are well supported by the conductivity measurement-the conductivity of acrylic acid doped polyaniline is higher than in case of polyanіline without acrylic acid.
Journal of Electroanalytical Chemistry, 1996
Poly (o-methoxyaniline) was chemically prepared in the presence of hydrochloric, p-toluene-sulfonic, dodecyl-benzene-sulfonic or dodecyl-sulfuric acids. Films of this polymer were prepared by casting and electrochemical, electrochromic and photoelectrochemical properties were studied. Cyclic voltammetry experiments show well-defined redox waves when the pH of the electrolyte is 1.0. Poly(o-methoxyaniline) films present high optical contrast in the visible range, when the potential is changed from the fully reduced to the fully oxidized state, independently of the dopant acid. The film obtained from the polymer doped with p-toluene-sulfonic acid, however, presents the highest contrast. Photoelectrochemical experiments also showed that this material yields photocurrent when irradiated with monochromatic light (330nm), and that the sign of the photocurrent depends on its oxidation state.
Russian Journal of Electrochemistry, 2004
Spectroelectrochemical properties of polyo-phenylenediamine (PPD) and the synthesized composite of PPD and polyaniline-two chemically related polymers containing an amino-substituted benzene ring but having different conduction nature-are studied. The polyaniline synthesis on PPD-modified electrodes involves stages of the reaction initiation, the copolymer formation, and the formation of a polyaniline layer at the copolymer/solution interface.
Effects of Dopant Ions on the Properties of Polyaniline Conducting Polymer
Oriental Journal of Chemistry
This work will show, for the first time, the effect of nicotinic acid (NA) and 2-methylnicotinic acid (MNA)on the synthesis and properties of conducting polyaniline (PANI). The work investigates the effects of sulphuric acid (H2SO4), nicotinic acid (NA), and 2-methylnicotinic acid (MNA) on the synthesis and properties of polyaniline. The results show that the preparation of polyaniline from a sulphuric acid electrolyte is faster than the preparation from nicotinic acid and 2- methylnicotinic acid electrolytes. Moreover, the electrical conductivity and thermal stability of PANI/H2SO4 were greater than PANI/NA and PANI/MNA. All the polymers prepared in this study were identified using FT-IR. Scanning electron microscopy (SEM) was used to examine the morphologies of the PANI samples, from which it was determined that PANI/H2SO4 has a fibrous and open structure with a higher porosity morphology compared to PANI/NA and PANI/MNA. The electrical conductivities of the PANI samples were meas...
Morphology and electrical properties of hybrid and sulphonated oxalic acid-doped polyaniline
Synthetic Metals, 2010
Polyaniline-polyethylene glycol2000 (PAni-PEG2000) hybrid and sulphonated polyaniline (SPAni) were prepared using oxalic acid as dopant and potassium permanganate as oxidant. The properties of these two conductive polymers were studied in comparison with pure polyaniline (PAni) prepared using the same conditions. The investigated polymers were characterized using FTIR, UV-vis, TGA, TEM, SEM, XRD and their electrical conductivities were also investigated. The morphology of pure polymer was found to be flat ribbon-like form, while presence of polyethylene glycol led to the formation of separate nanospheres. The three polymer samples have different degrees of crystallinity, the highest degree is for SPAni. Unexpectedly, electrical conductivity is in the order SPAni > PAni-PEG2000 > PAni, aging of PAni increases gradually the conductivity of the polymer from 0.0056 to 0.023 S cm −1 and the increase of temperature gradually decreases the conductivity.
ELECTRICAL CONDUCTIVITIES OF SYNTHESIZED POLY o-PHENYLENEDIAMINE AND ITS NANOCOMPOSITES
Poly (o-Phenylenediamine) and their metal oxide nanocomposites using different concentrations like 5%, 10% and 15% of SiO 2 nanoparticles were synthesized by chemical oxidative polymerization method using ammonium persulphate as an oxidant in the presence of HCl. The formation of polymers and their nanocomposites were confirmed from the UV-Vis and FT – IR spectroscopy. The formation of Poly (o-Phenylenediamine) nanocomposites were confirmed by the change of polymer colour from red to brown and found to exhibit band at 446nm in UV-visible spectroscopy. The crystalline nature of the synthesized polymers and their nanocomposites were determined from the XRD studies. The SEM images of the polymers recorded at different magnification shows rod like structure and found to change to flake like structures in the polymer nanocomposites synthesized at different concentration of SiO 2 nanoparticles. The TEM recorded at different angle confirms the core shell structures. The stability of the synthesized polymer and its nanocomposites were substantiated from thermal studies carried out using TGA, DTA and DSC. The comparative electrical conductivities of the polymer and its nanocomposites shows that the polymer nanocomposites exhibit higher conductivities compared to the polymer and the electrical conductivity was found to be higher for the polymer nanocomposite synthesized with 15% of SiO 2. The polymer and its nanocomposites show semiconducting nature.Conducting polymers consisting of conjugated electronic structures have received considerable attention in the field of material science due its promising technological applications 1. Among conducting polymers; polyaniline and its derivatives have attracted much attention due to its ease of synthesis 2-4. It has been demonstrated that organic compounds, in particular polymers have many interesting properties such as solubility, procesability, environmental stability, and electroactivity 5. Nanocomposites are generally defined as composites in which the components have at least one dimension (i.e., length, width or thickness) in the size range of 1-100 nm 6. Nanocomposites differ from traditional composites in a sense that interesting properties can result from the complex interaction of the nanostructured heterogeneous phases. In addition, nanoscopic particles of a material differ greatly in the analogous properties from a macroscopic sample of the same material 7 .Nanocomposites containing organic polymers and
Synthesis and Characterization of Polyaniline Based Conducting Polymers
Present work deals with the synthesis of Polyaniline, polynitro aniline, poly m-toludine and poly o-toludine polymers by chemical oxidation method using ammonium per sulfate as chemical oxidant. The yield of all polymers was higher than 90%.The synthesized polymeric material have been characterized by FTIR spectroscopy. FTIR and SEM studies of polymer show the structural and slight morphological changes with change in substituent in monomer units
Synthesis and Characterization of Conducting Polyaniline Doped with Polymeric Acids
Journal of Macromolecular Science, Part A, 2006
Conducting polymer composites have many interesting physical properties and important application potentials. Suitable combinations of metal nanoparticles with conductive polymers can result in composite materials having unique physical and chemical properties that can have wide application potential in diverse areas. In this work, copper nanoparticles were fabricated by electrical explosion of wire (EEW) in solution of polyacrylic acid (PAA) and ethanol. Conductive polyaniline-copper (PANI-Cu) composites have been synthesized by in-situ polymerization of aniline in the fabricated copper suspension. Optical absorption in the UV-visible region of these suspensions was measured in the range of 200-900 nm. Morphology and structure of the composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectra (FTIR). Pure copper nanoparticles were uniformly dispersed into the polymer matrix. Thermal stability of the composites was characterized by thermogravimetric analysis (TGA). Electrical conductivity measurements indicated that the conductivity of the composites was higher than that of pure polyaniline and increased with increasing content of copper.