Synthesis of poly(aniline‐co‐o‐toluidine) coatings and their corrosion‐protection performance on low‐carbon steel

Strongly adherent poly(aniline‐co‐o‐toluidine) coatings were synthesized on low‐carbon‐steel substrates by the electrochemical copolymerization of aniline with o‐toluidine with sodium tartrate as the supporting electrolyte. These coatings were characterized with cyclic voltammetry, ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and scanning electron microscopy. The formation of the copolymer with the mixture of monomers in the aqueous sodium tartrate solution was ascertained by a critical comparison of the results obtained from the polymerizations of the individual monomers, aniline and o‐toluidine. The optical absorption spectrum of the copolymer was drastically different from the spectra of the respective homopolymers, polyaniline and poly(o‐toluidine). The extent of the corrosion protection offered by poly(aniline‐co‐o‐toluidine) coatings to low‐carbon steel was investigated in aqueous 3% NaCl solutions by open‐circuit‐potential measurements and a potentiodynamic polarization technique. The results of the potentiodynamic polarization measurements showed that the poly(aniline‐co‐o‐toluidine) coatings provided more effective corrosion protection to low‐carbon steel than the respective homopolymers. The corrosion rate depended on the feed ratio of o‐toluidine used for the synthesis of the copolymer coatings. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:1868–1878, 2007     

Electrodeposition of free‐standing poly(o‐dihydroxybenzene‐co‐3‐methylthiophene) films with tunable fluorescence properties

Electrochemical copolymerization of o‐dihydroxybenzene (oDHB) and 3‐methylthiophene (3MeT) was successfully achieved in boron trifluoride diethyl etherate by direct anodic oxidation of the monomer mixtures, although the oxidation potentials of oDHB and 3MeT were quite different. The influence of the applied polymerization potential on the synthesis of the copolymers was investigated. The higher applied potential favored the incorporation of 3MeT units into the copolymers. The structure and properties of the copolymers were investigated with UV‐vis spectroscopy, fluorescence spectroscopy, FTIR spectroscopy, and thermal analysis. The novel copolymers had many advantages, including good redox activity, good thermal stability, and high electrical conductivity. Additionally, the copolymers fluorescence properties that were tunable through changes in the feed ratio of the monomer mixtures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of conducting homopolymers and copolymers of o‐anisidine and o‐toluidine in inorganic and organic supporting electrolytes

The influence of inorganic and organic supporting electrolytes on the electrochemical, optical, and conducting properties of poly(o‐anisidine), poly(o‐toluidine), and poly(o‐anisidine‐co‐o‐toluidine) thin films was investigated. Homopolymer and copolymer thin films were synthesized electrochemically, under cyclic voltammetry conditions, in aqueous solutions of inorganic acids (H₂SO₄, HCl, HNO₃, H₃PO₄, and HClO₄) and organic acids (benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, and adipic acid) at room temperature. The films were characterized by cyclic voltammetry, ultraviolet–visible spectroscopy, and conductivity measurements with a four‐probe technique. The ultraviolet–visible spectra were obtained ex situ in dimethyl sulfoxide. The optical absorption spectra indicated that the formation of the conducting emeraldine salt (ES) phase took place in all the inorganic electrolytes used, whereas in organic acid supporting electrolytes, ES formed only with oxalic acid. Moreover, the current density and conductivity of the thin films was greatly affected by the nature and size of the anion present in the electrolyte. For the copolymer, the conductivity lay between the conductivity of the homopolymers, regardless of the supporting electrolyte used. The formation of the copolymer was also confirmed with differential scanning colorimetry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2634–2642, 2003     

Glucose oxidase electrodes of poly(o‐anisidine), poly(o‐toluidine), and their copolymer as biosensors: A comparative study

Thin films of poly(o‐anisidine) (POA), poly(o‐toluidine) (POT), and their copolymer poly(o‐anisidine‐co‐o‐toluidine) (POA‐co‐POT) were electropolymerized in solutions containing 0.1M monomer(s) and 1M H₂SO₄ as an electrolyte through the application of a sequential linear potential scanning rate of 50 mV/s between ?0.2 and 1.0 V versus an Ag/AgCl electrode on a platinum electrode. A simple technique was used to construct glucose sensors through the entrapment of glucose oxidase (GOD) in thin films of POA, POT, and their copolymer POA‐co‐POT, which were electrochemically deposited on a platinum plate in phosphate and acetate buffers. The maximum current response was observed for POA, POT, and POA‐co‐POT GOD electrodes at pH 5.5 and at a potential of 0.60 V (vs Ag/AgCl). The phosphate buffer yielded a fast response in comparison with the acetate buffer in amperometric measurements. The POT GOD electrode showed a fast response and was followed by POA‐co‐POT and POA GOD electrodes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1877–1884, 2004     

Electrochemical synthesis of poly(2‐iodoaniline) and poly(aniline‐co‐2‐iodoaniline) in acetonitrile

Poly(2‐iodoaniline) (PIANI) and poly(aniline‐co‐2‐iodoaniline) [P(An‐co‐2‐IAn)] were synthesized by electrochemical methods in acetonitrile solution containing tetrabutylammonium perchlorate (TBAP) and perchloric acid (HClO₄). The voltametry of the copolymer shows characteristics similar to those of conventional polyaniline (PANI), and it exhibits higher dry electrical conductivity than PIANI and lower than PANI. The observed decrease in the conductivity of the copolymer relative to PANI is attributed to the incorporation of the iodine moieties into the PANI chain. The structure and properties of these conducting films were characterized by FTIR and UV‐Vis spectroscopy and by an electrochemical method (cyclic voltametry). Conductivity values, FTIR and UV‐Vis spectra of the PIANI and copolymer were compared with those of PANI and the relative solubility of the PIANI and the copolymer powders was determined in various organic solvents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1652–1658, 2003     

Composites of poly(2‐chloroaniline) and poly(o‐toluidine) with pumice and their application in the removal of chromium(VI) ions from aqueous solutions

Poly(2‐chloroaniline) (P2ClAn)/pumice (Pmc) and poly(o‐toluidine) (POT)/Pmc composites were synthesized via the chemical oxidative polymerization of 2‐chloroaniline and o‐toluidine in the presence of a dispersion of Pmc powders in water solvent with an (NH₄)₂S₂O₈ oxidant. The composites were characterized with Fourier transform infrared (FTIR) spectroscopy, thermo‐gravimetric/differential thermal analysis (TG‐DTA), and scanning electron microscopy devices. The presence of P2ClAn and POT in the structure of the composites was confirmed by FTIR. Theresults of analysis show strong interactions between the homopolymers and Pmc. The applicability of the P2ClAn/Pmc and POT/Pmc composites were investigated for the removal of Cr(VI) ions in water. Batch adsorption experiments were carried out as a function of pH, initial concentration, time, adsorbent dosage, and temperature. The batch sorption kinetics were tested, and the applicability of the Langmuir and Freundlich adsorption isotherms for this system was tested at 20 ± 1°C. An initial pH of 3.0 was most favorable for Cr(VI) removal by all adsorbents. The adsorption capacities obtained were 0.187 and 4.959 mmol/g of adsorbent for POT/Pmc and P2ClAn/Pmc from the Freundlich and Langmuir adsorption isotherms, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Copolymers of aniline and o‐methoxyaniline: Synthesis and characterization

High‐conversion (HC) copolymers of aniline and o‐methoxyaniline (o‐anizidine) were synthesized for the first time by chemical oxidative copolymerization using various polymerization techniques (simultaneous or consecutive introduction of comonomers into the polymerizing system). Low‐conversion (LC) copolymers have also been synthesized for comparison. The polymers obtained were characterized using ¹H‐NMR, infrared, and electronic absorption spectroscopy, differential scanning calorimetry, and electrical conductivity measurements. Solubility characteristics and composition of different fractions of the copolymers were also determined. It was shown that in contrast to the LC copolymers, HC copolymers reveal relatively poor solubility. Electrical conductivity of copolymers and also of o‐methoxyaniline homopolymer is lower compared to polyaniline, which correlates with notable hypsochromic (blue) shift of the bands in electronic absorption spectra. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 75–81, 2006     

Copolymers of aniline and o‐methoxyaniline: Synthesis and characterization

High‐conversion (HC) copolymers of aniline and o‐methoxyaniline (o‐anizidine) were synthesized for the first time by chemical oxidative copolymerization by using various polymerization techniques (simultaneous or consecutive introduction of comonomers into the polymerizing system). Low‐conversion (LC) copolymers have also been synthesized for comparison. The polymers obtained were characterized by using ¹H‐NMR, infrared, and electronic absorption spectroscopy; differential scanning calorimetry; and electrical conductivity measurements. Solubility characteristics and composition of different fractions of the copolymers were also determined. It was shown that, in contrast to the LC copolymers, HC copolymers reveal relatively poor solubility. Electrical conductivity of copolymers and also of o‐methoxyaniline homopolymer is lower as compared to polyaniline, which correlates with notable hypsochromic (blue) shift of the bands in electronic absorption spectra. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1822–1828, 2005     

Synthesis and characterization of poly(o‐ and m‐amino benzyl amine) and the copolymers with aniline. Study with Cu(II)

Poly(o‐amino benzyl amine), poly(m‐amino benzyl amine), and the copolymers with aniline were synthesized in 10^?4M HCl by using ammonium persulfate as oxidizing agent. The copolymers were synthesized at various feed mole fractions of comonomer diamine and characterized by elemental analysis, FTIR, ¹H‐NMR spectroscopy, and electrical conductivity. The polymerization yield depended on the substituent position in the aromatic ring. Copper ion was incorporated in the polymers and the amount depended on the side groups position in the aromatic ring. The thermal stability increased when copper ions and aniline units were incorporated in the polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 31–36, 2004     

Chemical grafting of aniline and o‐toluidine onto poly(ethylene terephthalate) fiber

Graft copolymerization of poly(aniline) and poly(o‐toluidine) onto poly(ethylene terephthalate) fiber was conducted by using peroxydisulfate as a lone initiator under nitrogen atmosphere at various experimental conditions in aqueous hydrochloric acid medium. The grafting of poly(aniline) and poly(o‐toluidine) onto poly(ethylene terephthalate) fiber was verified by recording cyclic voltammetry of the grafted fiber, conductivity measurements, and thermal analysis. Graft parameters—such as % grafting, % efficiency, and the rate of grafting—were followed. Grafting was always accompanied by homopolymerization. The rate of homopolymerization was also followed in all experimental conditions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 121–128, 1999     

Electrical conductivity and thermal properties of poly(m‐aminophenyl acetic acid) and its copolymers with aniline

Poly(m‐aminophenyl acetic acid) was synthesized under different conditions from the respective monomer, using ammonium persulfate as oxidizing agent in both the presence and the absence of CuCl₂ in HCl(aq). Moreover, the copolymers between aniline and m‐aminophenyl acetic acid were prepared at several feed mol ratios (f₁) of aniline. Copper was introduced by the Batch method in the homo‐ and copolymers of different compositions. The polymers were characterized by FTIR and UV‐vis spectroscopy, elemental analysis, thermal analysis, and electrical conductivity. The thermal stability and the content of copper increased as the content of aniline was increased in the copolymers. Moreover, the copolymers showed a high thermal stability; at 400°C a weight loss < 10% was observed. The electrical conductivity was increased with a higher content of aniline in the copolymers, achieving semiconduction values. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1484–1492, 2003     

Effect of microstructure on the dielectric properties of poly(vinyl alcohol)–poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) composite films

Poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT–PSS) was blended with poly(vinyl alcohol) (PVA) to form 0, 10, 20, 30, 40, and 50 vol % PEDOT–PSS/PVA solutions, and their freestanding films were prepared with a simple and cost‐effective solution casting technique at 27 °C in the absence of additives. Field emission scanning electron microscopy images revealed changes in the cocontinuous network to a rodlike morphology in the composite films from 10 to 50 vol % PEDOT–PSS/PVA. The alternating‐current conductivity was found to obey Jonscher's power law. The obtained values of the dielectric constant at 27 °C were relatively high, and a maximum value of 6.7 × 10⁴ at 100 Hz for 40 vol % PEDOT–PSS'/PVA was observed. The dielectric loss attained a maximum value of about 10⁶ at 100 Hz for 40 vol % PEDOT–PSS/PVA. However, a decrease in the dielectric parameters was observed at 50 vol % PEDOT–PSS/PVA because of locally induced strain in the microstructure. The variations in polarization with respect to the applied electric field (P–E) were determined for 50, 100, and 500 Hz at 500 V for the freestanding composite films of lower concentrations up to 20 vol % PEDOT–PSS/PVA. In summary, the dielectric and P–E measurements confirmed that the electrical characteristics changed in accordance to the contribution from both resistive and capacitive sites in the PEDOT–PSS/PVA composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45079.     

Preparation and characterization of aqueous dispersions of poly(3,4‐ethylenedithiathiophene‐co‐3,4‐ethylenedioxythiophene)/ poly(styrene sulfonate) and their conducting films

The chemical oxidative copolymerization of 3,4‐ethylenedithiathiophene (EDTT) with 3,4‐ethylenedioxythiophene (EDOT) and 2′‐hydroxymethyl‐3,4‐ethylenedioxythiophene in a poly(styrene sulfonic acid) aqueous solution was successfully carried out to form stable, dark blue colloidal dispersions in water. Coating these dispersions onto polypropylene substrates led to the formation of free‐standing copolymer films. The mechanical, electrical, and thermoelectrical properties of these films were investigated; the films showed superior properties in comparison with those of poly(3,4‐ethylenedithiathiophene) (PEDTT)/poly(styrene sulfonate) (PSS). The copolymer film based on EDTT and EDOT achieved a high electrical conductivity (8.2 × 10^?2 S cm^?1) at 298 K; this could be improved about 10 times through the addition of dimethyl sulfoxide (DMSO) or DMSO/isopropyl alcohol into the polymer dispersion with almost constant Seebeck coefficients of about 9 μV K^?1. On the contrary, these additives had almost no effect on the conductivity of PEDTT/PSS. The structure and morphology of the polymer films were studied by X‐ray diffraction and SEM analyses. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of novel polyfuran/poly(2‐iodoaniline) conducting composite

The electrically conducting polyfuran/poly(2‐iodoaniline) (PFu/P2IAn) and P2IAn/PFu composites were prepared by chemical oxidative polymerization using polyfuran and poly(2‐iodoaniline) in HCl and CHCl₃ media. The conductivities of composites were determined as a function of the amount of guest polymer. It was found out that the conductivities of P2IAn/PFu composites increased 100‐fold, whereas the conductivities of PFu/P2IAn composites did not show a specific increase. The composite compositions were altered by varying guest polymer feed ratios during preparation. Generally, the electrical conductivities of P2IAn/PFu composites increased with increasing the amount of PFu. Homopolymers and composites were further characterized thermally, employing thermogravimetry (TGA) and morphologically employing scanning electron microscopy (SEM). Further evidences concerning the polymer structures were obtained by FTIR and UV‐vis spectroscopies and magnetic susceptibility measurements. TGA results revealed that PFu/P2IAn among the homopolymers (PFu and P2IAn) and P2IAn/PFu composite have the highest thermal stability. The composites synthesized varying the host and the guest polymer order have different conductivities, morphological structures, and thermal properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2823–2830, 2003     

Studies on the dielectric properties of poly(o‐toluidine) and poly(o‐toluidine‐aniline) copolymer

Poly(o‐toluidine) (PoT) and poly(o‐toluidine co aniline) were prepared by using ammonium persulfate initiator, in the presence of 1M HCl. It was dried under different conditions: room temperature drying (48 h), oven drying (at 50°C for 12 h), or vacuum drying (under vacuum, at room temperature for 16 h). The dielectric properties, such as dielectric loss, conductivity, dielectric constant, dielectric heating coefficient, loss tangent, etc., were studied at microwave frequencies. A cavity perturbation technique was used for the study. The dielectric properties were found to be related to the frequency and drying conditions. Also, the copolymer showed better properties compared to PoT alone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 592–598, 2004     

Copolymers of aniline with o‐ and m‐toluidine: synthesis and characterization

Copolymers of aniline and toluidine were synthesized by oxidative chemical polymerization using different ratios of the monomers in the feed, and characterized by a number of techniques including UV–visible, IR, Raman, ¹H NMR and EPR spectroscopies, as well as by thermogravimetric analysis and conductivity measurements. The properties of the copolymers are influenced by the amount of toluidine in the copolymer. Poly(o‐toluidine) and poly(m‐toluidine) are noticeably different in their solubility and conductivity. The copolymers show better solubilities than polyaniline but have lower conductivities. Differences in the properties of the salt and base forms of the copolymers are pointed out. Copyright © 2003 Society of Chemical Industry     

Mechanochemical synthesis and characterization of poly(2,5‐dimethoxy aniline) salts

The interfacial interaction and orientation of molecules during the polymerization process plays a vital role in the enhancement of the surface properties of conducting polymers. In this perspective, a solid‐phase mechanochemical route is employed to prepare poly(2,5‐dimethoxy aniline) (PDMA) and its salts with superior properties. Various studies performed on the as‐prepared polymer highlights the formation of polymeric particles with excellent physicochemical properties. Elemental analysis showed the presence of dopants anion in the polymeric backbone. Spectroscopic profile of PDMAs revealed the formation of emeraldine form of PDMAs. Moreover, these studies indicate the formation of PDMA‐HCl in a highly doped state. The surface morphological pictures of PDMAs revealed the formation of aggregated microstructured to nanostructured particulates. X‐ray diffraction, cyclic voltammetry were used to evaluate the physicochemical properties of PDMAs. PDMA salts exhibited crystalline behavior and good electrochemical activity. TG/DTA analysis showed that all the PDMAs were thermally stable up to 240°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Electrochemical preparation of poly(2‐bromoaniline) and poly(aniline‐co‐2‐bromoaniline) in acetonitrile

Electrochemical preparation of poly(2‐bromoaniline) (PBrANI) and poly(aniline‐co‐2‐bromoaniline) [P(An‐co‐2‐BrAn)] was carried out in an acetonitrile solution containing tetrabutylammonium perchlorate (TBAP) and perchloric acid (HClO₄). The cyclic voltammograms during the copolymerization had many features similar to those for the usual polymerization of aniline. The copolymer exhibits a higher dry electrical conductivity value than that of PBrANI and a lower one than that of PANI. The observed decrease in the conductivity of the copolymer relative to PANI is attributed to the incorporation of bromine moieties into the polyaniline chain. The structure and properties of the polymer and copolymer were elucidated using cyclic voltammetry (CV), FTIR, and UV‐vis spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2460–2468, 2003     

Electrical properties of sorbitol‐doped poly(vinyl alcohol)–poly(acrylamide‐co‐acrylic acid) polymer membranes

Solid polymer membranes from poly(vinyl alcohol) (PVA) and poly(acrylamide‐co‐acrylic acid) (PAA) with varying doping ratios of sorbitol were prepared using the solution casting method. The films were examined with Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and AC impedance spectroscopy. The impedance measurements showed that the ionic conductivity of PVA–PAA polymer membrane can be controlled by controlled doping of sorbitol within the polymer blends. The PVA–PAA–sorbitol membranes were found to exhibit excellent thermal properties and were stable for a wide temperature range (398–563K), which creates a possibility of using them as suitable polymers for device applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of poly(amic acid) and polyimide derived from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride with different diamines by microwave irradiation

Polycondensation‐type poly(amic acid) (PAA) was synthesized with 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride as a dianhydride monomer and 4,4′‐diaminodiphenylmethane and 4,4′‐oxydianiline as diamine monomers under microwave irradiation in dimethylformamide. Then, PAA was used to make polyimide (PI) by imidization at a low temperature. The structure and performance of the polymers were characterized with Fourier transform infrared (FTIR), proton nuclear magnetic resonance (¹H‐NMR), viscosity, X‐ray diffraction (XRD), and thermogravimetry (TG) curve analyses. The FTIR spectra of the polymers showed characteristic peaks of PI around 1779 and 1717 cm^?1. The ¹H‐NMR spectrum of PAA indicated a singlet at 6.55 ppm assigned to ? NHCO? and a singlet at 10.27 ppm assigned to carboxylic acid protons. The XRD spectrum demonstrated that the obtained PI had a low‐order aggregation structure with a d‐spacing of 0.5453 nm. The TG results revealed that the PI was thermally stable with 10% weight loss at 565°C in an N₂ atmosphere. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008