Influence of pH of the reaction medium on the structure and property of conducting poly(o-phenylenediamine) (original) (raw)
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Influence of structure of poly(o-phenylenediamine) on the doping ability and conducting property
Ionics, 2016
Poly(o-phenylenediamine) with ladder-type structure was formed in aqueous hydrochloric acid medium below pH 1, while open ring-type amine derivative, i.e., −NH 2 functional group substitution of polyaniline structure, was obtained in 1:1 aqueous sulfuric acid medium from the chemical synthesis of the monomer o-phenylenediamine. However, poly(o-phenylenediamine) having structure like polyaniline derivative with free =NH functional groups was obtained by chemical synthesis in dimethyl sulfoxide medium. The laddertype polymer was almost insoluble but the other two types of synthesized polymers having polar functional group substitutions were well soluble in polar organic solvent like dimethyl sulfoxide, N,N-dimethyl formamide, and tetrahydrofuran. The freestanding films were cast from dimethyl sulfoxide solution of both the soluble functional polymers. The polymers having different structures were doped with inorganic acid by solution doping technique and the doped polymers were characterized by various standard characterizations. In order to explore the electronic uses of the polymers like sensor and actuators, the influences of their structure on the doping ability as well as ionic properties of the sulfuric acid-doped polymers were compared.
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 Conducting Polymer
International Journal of Scientific Research in Science and Technology, 2021
In recent technology, considerable attention was given to the fabrication of light weight rechargeable batteries, electro chromic display devices, microelectronics, sensor and molecule design etc. As one of the most important conducting polymers, polyaniline because of its chemical stability and relatively high conductivity and its derivatives have been extensively studied in different fields of science, because of the demand for high performance materials in advanced technologies. However, the common uses of polyaniline are restricted, due to its poor process ability and low solubility. Various techniques were given for synthesis of conducting polymer. In the current studies, polyaniline (PANI) and its composites with semiconductor was prepared chemical oxidation method in the presence of different bronsted acids from aqueous solutions. The effect of thermal treatment on electrical conductivity (DC), of the pure PANI, PANI+10%, 15% and 20% MnSO4 conducting polymers were investigated. It is found that conductivity of PANI enhancing due to stretching polymeric chain cause due to interaction with MnSO4.
Nanomaterials Application Properties 2013, 2013
p-Phenylenediamine (PDA) doped with different molar concentration of phthalic acid (PhA) was synthesized by chemical oxidative polymerization in the presence of ammonium peroxydisulfate as oxidant. Polyphenylenediamine was confirmed by FT-IR. The morphology of PDA was confirmed by scanning electron microscope (SEM); it was found that change from nanospheres to nanofibers due to increasing the concentration of phthalic acid. The thermal stability (TGA) and electrical conductivity of polyphenylenediamine was studying. From TGA, it was found that increasing the concentration of phthalic acid from 0.1-0.4M allow to form amide link which easy to rupture with increasing the temperature. It has been observed that the conductivity not affected by increasing in the temperatures, but it is affected by increasing the concentration of phthalic acid from 5.34 x 10-11 in 0.1M to 6.42 x 10-7 in 0.4M. The increase in conductivity may be due to the increase of efficiency of charge transfer between the polymer chains and the dopant.
A novel route for the synthesis of processable conducting poly(m-aminophenol)
Materials Chemistry and Physics, 2008
Polymerization of m-aminophenol (mAP) in aqueous NaOH solution was done chemically by using ammonium persulfate (APS) as an oxidative initiator. The product poly(m-aminophenol) (PmAP) was found to be highly soluble in aqueous sodium hydroxide, dimethyl sulfoxide (DMSO) and N,N-dimethyl formamide (DMF). From the intrinsic viscosity measurement, the optimum condition for the polymerization was established with 0.6 M NaOH medium with the ratio of monomer to oxidant as 1:1.5 (mol:mol). The polymer was characterized by FTIR and 1 H NMR spectroscopy, elemental (CHNS) and thermogravimetric (TGA) analyses. From the spectroscopic analysis the structure of the polymer was found to resemble that of hydroxy polyaniline as the polymer contains free-OH groups attached to o/m position in the phenyl ring. The elemental analysis of the polymer also confirmed the same. From TGA study, the polymer was found to be thermally stable. A freestanding film of poly(m-aminophenol) was cast in DMSO solution followed by solvent removal and drying of the film at 100 • C for 7-8 h in an oven. A dc conductivity of 4.8 × 10 −4 S cm −1 was obtained for the synthesized polymer film after doping with H 2 SO 4 solution.
Synthesis of poly(o-anisidine) with and without acrylic acid doping is carried out by chemical oxidative polymerization method. This is a new polymerization method for the direct synthesis of the emeraldine salt of poly(oanisidine), i.e. it is directly soluble in known organic solvent such as m-cresol, N-methyl pyrrolidone (NMP), DMSO, DMF, etc. without the need for a conversion of salt phase to base form. The reaction is unique since it eliminates the post processing step which involves neutralization of emeraldine salt to form emeraldine base and again reprotonating the base with a secondary protonic acid. The acrylic acid doped polymer prepared using tartaric acid is comparatively more soluble in m-cresol and NMP than the poly(o-anisidine) prepared without acrylic acid. UV-visible spectra for acrylic acid doped poly(o-anisidine) reveals the coil conformation at higher wavelength ~800-1000 nm along with sharp peak ~440 nm, which may be attributed to secondary doping due to extended coil conformation. Whereas in the presence of NMP as a solvent, the extended tail at higher wavelength disappears while a sharp peak (~630 nm) is observed representing the polymer insulting emeraldine base form. This fact confirms the effect of the solvent on the polymer properties. This is further manifested by the FT-IR spectral studies. Broad and intense band at ~3300-3200cm -1 and 1100-1200 cm -1 in acrylic acid doped polymer accounts for higher degree of doping. The conductivity of acrylic acid doped poly(o-anisidine) is greater than poly(oanisidine) without acrylic acid. The change in resistance of tartaric acid doped poly(o-anisidine) prepared in acrylic acid media upon its exposure to ammonia vapor suggests the applicability of these polymeric materials for ammonia.
Journal of Electroanalytical Chemistry, 2013
The physico-chemical characteristics of thin poly-(ortho-phenylenediamine) (PPD) films, obtained by electrochemical oxidation of the relevant monomer, are investigated using electrochemical, morphological and spectroscopic techniques. In particular, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques are used to collect information concerning the redox, conductivity and double layer capacitance properties of the PPD film. AFM imaging and Raman spectroscopy results are exploited to characterize the film structure. In this respect, Raman spectra of two possible PPD oligomers are calculated at the B3LYP/6-311G ÃÃ level of the theory.
Russian Journal of Electrochemistry, 2000
Electrochemical behavior of poly-o -phenylenediamine (P o PhD) films in lithium perchlorate and perchloric acid solutions of different pH and constant ionic strength is studied using cyclic voltammetry, low-amplitude chronoamperometry, chronopotentiometry, and faradaic-impedance spectroscopy. The experimental results point to the diffusion-migration kinetics of charge transfer processes in redox-active P o PhD films and show that two such processes occur during oxidation-reduction of P o PhD. The processes are separated most fully at low concentrations of hydronium ions. Effect of the electrode potential and electrolyte composition on these processes is examined. Different methods yield similar results and permit their more reliable interpretation.
Poly(bis-m-phenylenediaminosulphoxide) (PPDS) was prepared from Michael addition of N,N 0-bis-sul-phinyl-m-phenylenediamine and m-phenylenediamine. The prepared PPDS was then doped with iodine. PPDS was characterized by FTIR, 1 H-NMR, elemental microanalysis, thermogravimetric analysis (TGA), UV-visible absorption and fluorescence emission spectra. Thermal gravimetric analysis TGA showed that PPDS is thermally stable up to 179 C. Electronic transitions showed main absorption peak at l ¼ 340 nm and two emission peaks at 460 and 490 nm. The behavior of both dc and ac electrical conductivities of PPDS were studied. The direct current electrical conductivity (s dc) and the alternating current electrical conductivity (s ac) were enhanced by the physical doping of I 2 in the polymer matrix. The conduction mechanisms for dc and ac electrical conductivities have been investigated.
Application of poly(o-phenylenediamine) in rechargeable cells
Journal of Applied Electrochemistry, 2004
The electrochemical synthesis of poly(o-phenylenediamine) (PoPD) from an aqueous medium was suitably modified by controlling the switching potential to enhance the growth of the polymer. The charge-discharge data for the cell Zn/1 M ZnSO 4 (pH 4)/PoPD are presented. The polymer was modified by incorporating Pt microparticles into its matrix during electropolymerization. The PoPD-Pt composite electrode was also characterized as a cathode active material in aqueous cells.