D. D. Borole

Influence of inorganic and organic supporting electrolytes on the electrochemical synthesis of polyaniline, poly(o-toluidine) and their copolymer thin films

The influence of inorganic and organic supporting electrolytes on electrochemical, optical and conducting properties of polyaniline (PA), poly(o-toluidine) (POT) and poly(aniline-co-o-toluidine) (PA–POT) thin films have been investigated. The films were synthesized electrochemically individually and then combinedly as copolymer under cyclic voltammetric conditions in aqueous solutions of inorganic acids viz. H2SO4, HCl, HNO3, H3PO4 and HClO4 and organic acids viz. benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid and adipic acid at room temperature. The electrosynthesized films were characterized by cyclic voltammetry, UV–visible spectroscopy and conductivity measurement using four-probe technique. It was observed that the current densities are strongly influenced by the size and the nature of the anion present in the electrolyte. The optical absorption spectra indicate the formation of the conducting emeraldine salt (ES) phase irrespective of the inorganic electrolytes, whereas it shows dependence on organic acid supporting electrolytes. Among organic acids, the formation of thin films by cyclic voltammetry and the conducting ES phase was observed only in the case of oxalic acid. It was also found that the conductivity of thin films is greatly affected by the nature and size of the anion present in the electrolyte.

Effect of inorganic dopants (in presence of electrolyte) on the conductivity of polyaniline, poly(o-toluidine) and their copolymer thin films

Abstract An attempt has been made to prepare polyaniline (PA), poly(o-toluidine) (POT) and copolymer (PA-POT) thin films doped by several inorganic salts (sulphates and chlorides) with varying size of cation using aqueous solution of H2SO4 as electrolyte. Effect of dopant in presence of electrolyte is rarely studied in the field of conducting polymers. Various inorganic salts as dopants, viz. K2SO4, Na2SO4, Li2SO4, MgSO4, KCl, NaCl, LiCl and MgCl2 are used at room temperature. The films were electropolymerized in solution containing 0.1 M monomer, 1 M H2SO4 as electrolyte and 1 M inorganic salt by applying sequential linear potential scan rate 50 mV/s between −0.2 and 1.0 V versus Ag/AgCl electrode. The electrosynthesized films were characterized by cyclic voltammetry, UV–visible spectroscopy and conductivity measurements using four-probe technique. It was observed that the UV–visible peaks are appearing at about 800–810 nm with a shoulder at 410–420 nm for emeraldine salt (ES) phase of PA, POT and PA-POT without any doping salt. In the presence of salts, a shift for these absorption spectra is observed to lower wavelength in 760–800 nm, however, a shift of shoulder is to higher wavelength in 435–445 nm. In the overall study, an increase in conductivity is observed for all above-mentioned dopants, and among these, K2SO4 is found to be the best in sulphate category and KCl in chloride category.

Studies on electrochemical, optical and electrical conductivity characteristics of copolymer of polyaniline-co-poly(o-toluidine) using various organic salts

An attempt has been made to prepare polyaniline (PA), poly(o-toluidine) (POT) and their copolymer polyaniline-co-poly(otoluidine) (PA–POT) thin films doped by several organic salts with varying size of cation, using aqueous solution of H2SO4 as electrolyte. Effect of dopant in the presence of electrolyte is rarely studied in the field of conducting polymers. Various organic salts as dopants, viz. potassium acetate, sodium acetate and magnesium acetate were used at room temperature. The films were electropolymerized in solution containing 0.1 M monomer(s), 1 M H2SO4 as electrolyte and 1 M organic salt by applying sequential linear potential scan rate 50 mV/s between 0.2 and 1.0 V versus Ag/AgCl electrode. The electro-synthesized films were characterized by cyclic voltammetry, UV–Visible spectroscopy and conductivity measurements. The UV–Visible spectra were obtained ex situ in dimethyl sulfoxide (DMSO) and peaks are observed to appear at about 800–810 nm with a shoulder at 410–420 nm are for emeraldine salt (ES) phase of PA, POT, PA–POT without any doping salt. In the presence of salts, a shift for these absorptions was observed to lower wavelength (758–786 nm), however, a shift of shoulder to higher wavelength (413–425 nm). In overall study, an increase in conductivity was observed for all aforesaid dopants and among these, potassium acetate was found to be the best. D 2003 Elsevier Science B.V. All rights reserved.

Studies on Influence of Inorganic Dopants in Presence of Electrolyte on the Conductivity of Polyaniline, Poly(o-Anisidine), and Their Copolymer Thin Films

An attempt was made to prepare polyaniline (PA), poly(o-anisidine) (POA), and copolymer polyaniline–poly(o-anisidine) (PA–POA) thin films dopped by several inorganic saltas (sulfates and chlorides) with varying sizes of cations using an aqueous solution of H2SO4 as an electrolyte. Various inorganic salts as dopants, viz., K2SO4, Na2SO4, Li2SO4, MgSO4, KCl, NaCl, LiCl, and MgCl2, were used at room temperature. The films were electropolymerized in solution containing 0.1-M monomer(s), 1-M H2SO4 as electrolyte, and 1-M inorganic salt by applying sequential linear potential scan rate 50 mV/s between −0.2 to 1.0 V vs Ag/AgCl electrode. The electrosynthesized films were characterized by cyclic voltammetry, UV–visible spectroscopy, and conductivity measurements, using a four-probe technique. It was observed that the UV–visible peaks usually appearing at about 810 to 826 nm with a shoulder at 416 to 426 nm, showed a shift in presence of doping salt for the emeraldine salt (ES) phase of PA, POA, PA–POA. In the overall study, a significant increase in conductivity is observed for all dopants mentioned above, and among them K2SO4, is found to be the best in sulfate category and KCl in chloride category.

Electrochemical synthesis of poly(o-anisidine), poly(o-toludine) and their copolymers in organic sulphonic acid

The effect of organic sulphonic acids on electrochemical, optical and conductivity properties of poly( o -anisidine) (POA), poly( o -toluidine) (POT) and poly(o-anisidine-co-o-toluidine) (POA-co-POT) thin films has been investigated. The films were synthesized electrochemically, individual as homopolymers and then combined as (binary copolymer) under cyclic voltammetric conditions in an aqueous solution of sulphuric acid, p-toluene sulphonic acid, sulphamic acid and sulphosalicylic acid at room temperature. The films were electropolymerized in solution containing 0.1 M monomers and respective electrolyte (1 M sulphuric acid or organic sulphonic acid) by applying sequential linear potential scan rate of 50 mV/s between-0.2 and 1.0 V versus Ag/AgCl electrode. The electrosynthesized films were characterized by cyclic voltammetry, UV-Vis spectroscopy and conductivity measurement. It is observed that the UV-Vis peaks for sulphuric acid, p-toluene sulphonic acid, sulphamic acid and sulphosalicylic acid appear in the region of the conducting emeraldine salt (ES) phase. Overall, the polymers prepared using all these three organic sulphonic acids have higher conductivity than sulphuric acid; however, the higher conductivity is observed for p-toluene sulphonic acid as electrolyte in comparison with sulphamic acid and sulphosalicylic acid. The formation of copolymer (POA-co-POT) has been supported and confirmed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) studies. A possible scheme of reaction mechanism for homo- and copolymer has been suggested.

Influence of Organic Sulfonic Acids on the Electrochemical Synthesis of Polyaniline, Poly( o -Anisidine), and Their Copolymer

Abstract The effect of organic sulfonic acid on electrochemical, optical, and conductivity properties of polyaniline (PA), poly(o-anisidine) (POA), and their copolymer polyaniline-co-poly(o-anisidine) (PA-co-POA) thin films has been investigated. The films were synthesized electrochemically individually and then combinely as binary co-polymerization under cyclic voltammetric conditions in an aqueous solution of sulfuric acid, p-toluene sulfonic acid, sulfamic acid, and sulfosalicylic acid at room temperature. The films were electropolymerized in solution containing 0.1 M monomers and 1 M sulfuric acid or organic sulfonic acid as electrolyte by applying sequential linear potential scan rate 50 mV/s between − 0.2 and 1.0 V vs. Ag/AgCl electrode. The electrosynthesized films were characterized by cyclic voltammetry, UV–Visible spectroscopy, and conductivity measurement. The UV–Visible spectra were obtained ex situ in DMSO and peaks were observed for conducting the emeraldine salt (ES) phase in the presence of sulfuric acid, p-toluene sulfonic acid, sulfamic acid, and sulfosalicylic acids. In overall study, it was observed that all these three organic sulfonic acids used as electrolyte showed higher conductivity than sulfuric acid, however, the highest conductivity was observed for p-toluene sulfonic acid as electrolyte in comparison with sulfamic acid and sulfosalicylic acid, in homo- and co-polymerization of aniline and o-anisidine.

Electrochemical Synthesis and Characterization of Homo- and Copolymer of Aniline and o-Anisidine in Various Organic Salts

Abstract An attempt has been made to prepare polyaniline (PA), poly (o-anisidine) (POA), and their copolymer poly (aniline-co-o-anisidine) (PA-co-POA) thin films dopped by several organic salts with varying size of cation, using an aqueous solution of H2SO4 as the electrolyte. The effect of using a dopant in presence of an electrolyte is studied less in the field of conducting polymers. Various organic salts, viz., potassium acetate, sodium acetate, and magnesium acetate were used as dopants at room temperature. The films were electropolymerized in solution containing 0.1 M monomer(s), 1 M H2SO4 as electrolyte, and 1 M organic salt by applying the sequential linear potential scan rate 50 mV/s between − 0.2 and 1.0 V vs. Ag/AgCl electrode. The electrosynthesized films were characterized by cyclic voltammetry, UV–Visible spectroscopy, and conductivity measurements. The UV–Visible spectra were obtained ex situ in DMSO and peaks were observed to appear at about 810–826 nm with a shoulder at 416–426 nm for the emeraldine salt (ES) phase of PA, POA, and PA-co-POA without any doping salt. In the presence of salts, a shift for these absorptions was observed to lower wavelength (786–810 nm); however, a shift of shoulder to higher wavelength (424–435 nm) occurred. In the overall study, an increase in conductivity was observed for all aforesaid dopants; among these, potassium acetate was found to be the best.

Electrochemical synthesis and characterization of the conducting copolymer poly(aniline-co-o-anisidine-co-o-toluidine)

Copolymerization of aniline, o-anisidine and o-toluidine was achieved electrochemically in aqueous solution containing H2SO4 as supporting electrolyte. The copolymer compositions can be altered by varying the monomer feed ratios during electrosynthesis. The films were electropolymerized in solution containing monomers in various ratios (0.025 to 0.1 M) and 1 M sulphuric acid as electrolyte by applying a sequential linear potential scan rate of 50 mV/s between -0.2 to 1.0 V versus Ag/AgCl electrode. The copolymers were characterized by cyclic voltammetric, conductivity measurement, UV-Vis spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), CHN elemental analysis and optical microscopy photographs.

Influence of TiO2 and SiO2 on Electrochemical, Optical and Electrical Conductivity of Polyaniline, Poly(o-toluidine) and Their Co-polymer

A conducting composite of polyaniline, poly(o-toluidine) and poly(aniline-co-o-toluidine) using incorporation of TiO2 and SiO2 was prepared by electrochemical polymerization. The films were electro-polymerized in solution containing 0.1 M monomer(s), 1 M sulphuric acid as supporting electrolyte and 10−5 M TiO2 and SiO2, applying a sequential linear potential scan rate of 50 mV/s between −0.2 and 1.0 V versus Ag/AgCl electrode. The characterization of the composites was done by cyclic voltammetry, UV-Vis spectroscopy, electrical conductivity and thermogravimetric analysis. It is observed that the UV-Vis peaks are appearing in the region of conducting emerladine salt (ES) phase. In overall study, the polymers prepared using TiO2 have higher conductivity than SiO2, with the highest conductivity observed for the polyaniline–TiO2 conducting composite. The composite does not lose its colour at higher temperature and, hence, can be utilized as conductive pigments required for anti-electrostatic applications.

Studies on Electrochemical, Optical and Electrical Conductivity of Conducting Composite of o-Anisidine, o-Toluidine and Their Co-polymer

A conducting composite of poly(o-anisidine), poly(o-toluidine) and poly(o-anisidine-co-o-toluidine) using incorporation of TiO2 and SiO2 was prepared by electrochemical polymerization. The films were electropolymerized in solution containing 0.1 M monomer(s), 1 M sulphuric acid as supporting electrolyte and 10–5 M TiO2 and SiO2 by applying a sequential linear potential scan rate of 50 mV/s between –0.2 and 1.0 V versus an Ag/AgCl electrode. The characterization of the composites was done by cyclic voltametry, UV-Vis spectroscopy, electrical conductivity and thermogravimetric analysis. It is observed that the UV-Vis peaks appear in the region of the conducting emerladine salt (ES) phase. Overall, the polymers prepared using TiO2 have higher conductivity than SiO2, with poly(o-toluidine)–TiO2 conducting composite having the highest conductivivty. The composite does not lose its colour at higher temperature and, hence, can be utilized as conductive pigments required for anti-electrostatic applications.