Thermally processable conducting polyaniline (original) (raw)
Macromolecules, 2000
New solution processing systems were studied with the goal to obtain highly conductive polyaniline films with good mechanical properties and its conducting blends with poly(methyl methacrylate). A new dopant, namely, 1,2-benzenedicarboxylic acid, 4-sulfo, 1,2-di(2-ethylhexyl) ester (DEHEPSA), was studied as a protonating agent. It was found that the use of this dopant together with dichloroacetic acid (DCAA) or difluorochloroacetic acid (DFCAA) as solvents leads to films showing conductivities of 180 and 100 S/cm, respectively. Films cast from DCAA are metallic in character down to 220 K. Since the protonation agent used exhibits doping as well as plasticizing properties, the resulting polyaniline films, in addition to high conductivity, show excellent flexibility and much lower glass-transition temperature, T g, (280 K) as compared to polyaniline doped with other protonating agents. Moreover, the same processing system can be used for the fabrication of polyaniline-poly(methyl methacrylate) blends with low percolation threshold (much below 1 wt % of PANI). Upon casting, the overwhelming majority of the solvent can be efficiently removed from the polymer matrix, whereas the remaining residual solvent is strongly bound to the polymer matrix. For this reason, the resulting blends do not show the disadvantages of the blends cast from m-cresol which release the residual solvent upon aging.
Polyaniline. Preparation of a conducting polymer(IUPAC Technical Report)
Pure and Applied Chemistry, 2002
Eight persons from five institutions in different countries carried out polymerizations of aniline following the same preparation protocol. In a "standard" procedure, aniline hydrochloride was oxidized with ammonium peroxydisulfate in aqueous medium at ambient temperature. The yield of polyaniline was higher than 90 % in all cases. The electrical conductivity of polyaniline hydrochloride thus prepared was 4.4 ± 1.7 S cm-1 (average of 59 samples), measured at room temperature. A product with defined electrical properties could be obtained in various laboratories by following the same synthetic procedure. The influence of reduced reaction temperature and increased acidity of the polymerization medium on polyaniline conductivity were also addressed. The conductivity changes occurring during the storage of polyaniline were monitored. The density of polyaniline hydrochloride was 1.329 g cm-3. The average conductivity of corresponding polyaniline bases was 1.4 x108 S cm-1, the ...
Polyaniline Conducting Electroactive Polymers Thermal and Environmental Stability Studies
E-Journal of Chemistry, 2006
In the current studies, polyaniline (PANi) was prepared both chemical and electrochemically in the presence of different bronsted acids from aqueous solutions. The effect of thermal treatment on electrical conductivity, and thermal stability of the PANi conducting polymers were investigated using 4-point probe and TGA techniques respectively. It was found that polymer prepared by CV method is more thermally stable than those prepared by the other electrochemical techniques. In this paper we have also reviewed some fundamental information about synthesis, general properties, diverse applications, thermal and environmental stability of polyaniline conducting polymers.
Materials Letters, 2007
It is demonstrated that polyaniline salt, obtained by simple protonation of its base form with 4,4-bis(4-hydroxy phenyl)-valeric acid (HPVA), combines solution processibility with electrical conductivity. The solution of PANI-HPVA in DMF and m-cresol mixture has been characterized by UV-vis spectroscopy, exhibiting spectral features characteristic of the protonated state. Precipitation of dissolved PANI-HPVA with chloroform, leads to powder of spherical morphology with an average particle size of 400 nm which is amorphous by X-ray. Their conductivity is ca. 10 − 3 S/cm (measured for pressed pellets). Thermogravimetric investigations indicate good thermal stability of this novel form of polyaniline, however some weight loss is observed below 200°C, associated with the removal of minute amounts of solvent entrapped within PANI-HPVA grains in the precipitation process. PANI-HPVA has film forming properties and free standing films (conductivity ca. 10 − 4 S/cm) can be obtained by dissolving the powders in DMF, followed by casting.
Synthesis and Characterization of Polyaniline
International Journal for Research in Applied Science and Engineering Technology, 2019
Synthesis of polyaniline as the main approach to obtain electroactive and conducting composite materials. Conducting composite material formed in the form of semiconductor. Organic polymer semiconductor material like polyaniline (polymeraldine salt) can be easily synthesized and it is the only conducting polymer material whose electronic structure and electrical properties can reversibly controlled by oxidation and protonation. PANI exist in three state leucomeraldine, emerldine,pernigraniline. But only emerldine salt shows conducting nature in the form of semiconductor. PANI used various applications, they can replace metals and semiconductors, because they have conductivity feature, low density, and easy process ability.Polyaniline is a representive from the family of conducting polymerhaving high environmental stability. This paper shows chemical method for synthesis of Polyaniline and compare its semiconducting properties with conventional semiconductor.
Novel Pva Proton Conducting Membranes Doped with Polyaniline Generated by In-Situ Polymerization
Electrochimica Acta, 2016
The main objective of this study consists in developing a new solid electrolyte gel-based type composite with acrylic acid (AA) and polyvinyl alcohol (PVA). These novel PVA conducting membranes containing polyaniline (PANI) were synthesized via in-situ polymerization of aniline (AN). The morphology and electrical properties of PVA/AA/AN/APS/MBA membranes were investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Ultraviolet-Visible Spectroscopy (UV-Vis), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA) and by Electrochemical Impedance Spectroscopy (EIS) respectively. These characterization studies reveal structural interactions between PANI and PVA due to channeling microstructure organization which thereby lead to an increase in proton conductivity up to 80%. Thus obtained PANI-PVA novel membranes could be used in semiconductor type applications.
European Polymer Journal, 2013
Polyaniline (PANI) samples were prepared by the oxidation of aniline with ammonium peroxodisulfate in a reaction vessel placed in a bath thermostated to particular temperature, T b , from À20°C to 40°C. Temperature-time profiles of reaction mixtures were monitored except for the reaction at À20°C that proceeded in the solid state. The temperature regime was found to influence the molecular structure, morphology, crystallinity and electrical conductivity of PANI. The increase in T b results in an increased content of meanwhile unspecified structure defects in the formed PANI chains (the presence of attached self-doping groups is improbable), decreased crystallinity, toughness and compactness of PANI microparticles and increased steepness of the temperature dependence of PANI conductivity. The PANI prepared in the solid-state polymerization at À20°C shows, besides a rather high crystallinity, the unusually high position of the quinonoid band maximum: 643 nm, which suggests a high regularity of its chains. A correlation between the temperature dependence of PANI conductivity at low temperatures (range from 13 to 318 K) on one hand and the temperature regime of PANI preparation on the other hand, is reported for the first time. The dependences obtained only poorly meet the variable random hopping model.
Effects of Dopant Ions on the Properties of Polyaniline Conducting Polymer
ORIENTAL JOURNAL OF CHEMISTRY, 2018
This work will show, for the frst 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 identifed 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 fbrous and open structure with a higher porosity morphology compared to PANI/NA and PANI/MNA. The electrical conductivities of the PANI samples were measured as 1.09 S cm-1, 0.65 S cm-1 and 0.089 S cm-1 for PANI/H2SO4, PANI/NA and PANI/MNA, respectively. The thermal stability of PANI was examined using the Thermogravimetric Analysis (TGA) technique. PANI/H2SO4 was found to degrade between 450-500°C, while PANI/NA and PANI/MNA decomposed at temperatures between 300-400°C.