Synthesis,Electrical, Electronic and Charge Transport Properties of Poly(aniline‐co‐p‐toluidine)

Copolymers of aniline with p‐toluidine were synthesized for different molar ratios of the respective monomers in acid medium. The electrical conductivity, charge transport and spectral characteristics upon incorporation of p‐toluidine units into the polyaniline backbone were investigated. The electrical conductivity of the copolymers showed frequency dependence which became more prominent with an increase in the number of p‐toluidine units in the polyaniline backbone. A direct relationship between the frequency dependence and electron localization was observed in the copolymers. Electronic spectra showed blue shifts in the π→π*and benzenoid→quinoid transitions revealing a decrease in the extent of conjugation in the copolymers. The protonated forms of the copolymers were soluble in DMSO giving polaron band around 400 nm. The decrease in electrical conductivity was attributed to the greater electron localizations as revealed from the broader ESR signals. Temperature dependence of electrical conductivity showed that charge transport was mainly through variable range hopping though a mixed conduction behavior was observed at higher temperature range.     

Conductive Nanocomposites Based on Cellulose Nanofibrils Coated with Polyaniline-DBSA Via In Situ Polymerization

Summary: Cellulose nanofibrils (CNF) were extracted by acid hydrolysis from cotton microfibrils and nanocomposites with polyaniline doped with dodecyl benzenesulphonic acid (PANI-DBSA) were obtained by in situ polymerization of aniline onto CNF. The ratios between DBSA to aniline and aniline to oxidant were varied in situ and the nanocomposites characterized by four probe DC electrical conductivity, ultraviolet-visible-near infrared (UV-Vis - NIR) and Fourier-transform infrared (FTIR) spectroscopies and X-ray diffraction (XRD). FTIR and UV-Vis/NIR characterization confirmed the polymerization of PANI onto CNF surfaces. Electrical conductivity of about 10⁻¹ S/cm was achieved for the composites; conductivity was mostly independent of DBSA/aniline (between 2 and 4) and aniline/oxidant (between 1 and 5) molar ratios. X-ray patterns of the samples showed crystalline peaks characteristic of cellulose I for CNF samples, and a mixture of both characteristic peaks of PANI and CNF for the nanocomposites. Field emission scanning electron microscopy (FESEM) characterization corroborated the abovementioned results showing that PANI coated the surface of the nanofibrils.     

Highly conductive soluble terpolymers of aniline,toluidine, and o‐aminobenzoic acid/m‐aminobenzenesulfonic acid

Two series of terpolymers, one of o‐/m‐toluidine and aniline with o‐aminobenzoic acid and the other of o‐/m‐toluidine and aniline with m‐aminobenzenesulfonic acid, have been synthesized by oxidative polymerization via an emulsion method with ammonium persulfate as the oxidant and HCl as the external dopant. The terpolymers exhibit excellent solubility and retain the high conductivity (∼1 S cm⁻¹) characteristic of the unsubstituted homopolymer, polyaniline. The terpolymers also possess higher thermal stability than polyaniline. This can be attributed to the presence of internal doping groups and substituents, which introduce flexibility to the otherwise rigid polyaniline backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3040–3048, 2005     

Synergistic effect of copolymers composition on the electrochemical,thermal, and electrical behavior of 5‐lithiosulphoisophthalic acid doped poly(aniline‐co‐2‐isopropylaniline): synthesis,characterization, and applications

The paper reports the synergistic effect of substituent, i.e. isopropyl group on electrical, thermal, and processability of polyaniline in the presence of 5‐lithiosulphoisophthalic acid (LiSIPA). The presence of substituent not only affects the electrochemical redox behavior of polyaniline but also brings changes in the optical and electronic properties of polyaniline. Evaluation of the copolymers as corrosion inhibitor for iron in 1.0 N HCl using electrochemical impedance spectroscopy and Tafel extrapolation method shows that the copolymers and homopolymer show corrosion inhibition efficiency ranging from 69 to 80% depending upon the composition of the copolymers. The copolymers doped with LiSIPA were soluble in organic solvents like methanol, ethanol, isopropanol, N‐methyl pyrrolidinone, and chloroform. The compositions of the copolymers were determined by ¹H NMR spectroscopy. The conductivity of the polymers was found to be in the order of 4.9 to 10^?3 S cm^?1 depending upon the comonomer ratios and concentration of dopant. Cyclic voltammetry of the copolymers shows a shift in peak potential value from 0.157 to 0.398 V when the monomer ratio of aniline to 2‐isopropylaniline in the polymerization reaction was changed from 0.9:0.1 to 0.5:0.5. The polymers were characterized by FTIR and UV‐visible spectroscopy, NMR, X‐ray diffraction, TGA, DSC, and cyclic voltammetry. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis,structure characterization,and gas sensitive properties of a copolymer of aniline with phenol

A new kind of conductive copolymers of aniline with phenol was designed and synthesized by using oxidation polymerization and the results showed that the apparent inherent conductivities of the copolymers are in the range of 10^?2 to 10^?10 S/cm which covers from conductors to insulators. The results showed that the conductivity of the copolymers strongly depends on synthesis conditions, such as reaction time, molar ratios of oxidizer to monomers and aniline to phenol, concentrations of reactants, and reaction temperature. Compared to the conventional (co)polymers of aniline and its derivatives, the magnitudes of the reversible conductivity changes are very significant, about two orders, and get to the maximum readings in about 5 min when they are exposed to ammonia gas, hydrochloric acid gas, and a various vapors of organic compounds, such as methanol, alcohol, acetone, benzene, toluene, chloroform, carbon tetrachloride, etc. It should be noted that with the introduction of the weak acidic structural units into the polyaniline chains, the copolymers are reversibly responded to both acidic and basic gases promptly. Copyright © 2009 John Wiley & Sons, Ltd.     

Self‐assembled anionic micellar template for polypyrrole,polyaniline, and their random copolymer nanomaterials

We report an anionic surfactant approach for size and shape control in polyaniline, polypyrrole, and their polyaniline‐co‐polypyrrole random copolymer nanomaterials. A renewable resource azobenzenesulfonic acid anionic surfactant was developed for template‐assisted synthesis of these classes of nanomaterials. The surfactant exists as 4.3 nm micelle in water and self‐organizes with pyrrole to produce spherical aggregates. The sizes of the spherical aggregates were controlled by water dilution and subsequent oxidation of these templates, produced polypyrrole nanospheres of 0.5 μM to 50 nm dimensions. The anionic surfactant interacts differently with aniline and forms cylindrical aggregates, which exclusively produce nanofibers of ∼180 nm in diameter with length up to 3–5 μM. The template selectivity of surfactant toward aniline and pyrrole was used to tune the nanostructure of the aniline‐pyrrole random copolymers from nanofiber‐to‐nanorod‐to‐nanospheres. Dynamic light scattering technique and electron microscopes were used to study the mechanistic aspects of the template‐assisted polymerization. The four probe conductivity of the copolymers showed a nonlinear trend and the conductivity passes through minimum at 60–80% of pyrrole in the feed. The amphiphilic dopant effectively penetrates into the crystal lattices of the polymer chain and induces high solid state ordering in the homopolymer nanomaterials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 830–846, 2009     

Effect of the sulfonic acid group on copolymers of aniline and toluidine with m‐aminobenzene sulfonic acid

This article describes the results of the preparation and characterization of self‐doped conducting copolymers of aniline and toluidine with m‐aminobenzene sulfonic acid. The copolymers have an intrinsic acid group that is capable of doping polyaniline. Spectroscopic, morphological, and electrical conductivity studies have provided insight into the structural and electronic properties of the copolymers. The differences in the properties of polyaniline and polytoluidine due to the sulfonic acid ring substituent on the phenyl ring are discussed. The scanning electron micrographs of the copolymers reveal regions of sharp‐edged, needle‐shaped structures, whereas the X‐ray diffraction patterns show that the copolymers are relatively more crystalline in nature. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4065–4076, 2002     

A new route to obtain PVDF/PANI conducting blends

Electrically conductive poly(vinylidene fluoride)(PVDF) - polyaniline blends of different composition were synthesized by chemical polymerization of aniline in a mixture of PVDF and dimethylformamide (DMF) and studied by electrical conductivity measurement, UV-Vis-NIR and FTIR spectroscopy. The samples were obtained as flexible films by pressing the powder at 180 °C for 5 min. The electrical conductivity showed a great dependence on the syntheses parameters. The higher value of the electrical conductivity was obtained for the oxidant/aniline molar ratio equal to 1 and p-toluenesulfonic acid-TSA/aniline ratio between 3 and 6. UV-Vis-NIR and FTIR spectra of the blend are similar to the doped PANI, indicating that the PANI is responsible for the high electrical conductivity of the blend. The electrical conductivity of blend proved to be stable as a function of temperature decreasing about one order at temperature of 100 °C. The route used to obtain the polymer blend showed to be a suitable alternative in order to obtain PVDF/PANI-TSA blends with high electrical conductivity.     

Effect of aromatic substitution in aniline on the properties of polyaniline

Substitution in aniline has tremendous effect in the synthesis of poly(substituted anilines) as well as in their properties. In this investigation polyaniline (PANI), poly(m-nitro aniline) (PMNA), poly(m-amino phenol) (PMAP) and poly(o-ethyl aniline) (POEA) were synthesized by oxidative polymerization under identical conditions. Different properties were measured and compared with PANI to find out the presence of electron donating -OH group, electron withdrawing -NO₂ group and less effecting ethyl group on the properties of poly(substituted anilines). It was found that presence of any type of substitution in the benzene ring of aniline increases the solubility of the resulted polymer but reduces the yield, degree of polymerization, thermal stability, electrical and thermal conductivity. The colors, bulk density, particle size, percentage of crystallinity vary considerably depending on the nature of substitution.     

Donor–acceptor‐based poly(toluidine‐co‐chloroaniline)s: Synthesis and characterization

A series of poly(o‐/m‐toluidine‐co‐o‐/m‐chloroaniline) copolymers of different compositions were synthesized by an emulsion method with ammonium persulfate as the oxidant. The conductivity of the copolymers was two to five orders of magnitude higher than that of the homopolymers poly(o‐toluidine) and poly(m‐chloroaniline). Among the copolymers, the copolymer of o‐toluidine and m‐chloroaniline exhibited a maximum conductivity of 0.14 S cm^?1. The conductivity of these copolymers was also higher than that of poly(aniline‐co‐chloroaniline). The properties of the copolymers were greatly influenced by the positions of the substituents and the concentrations of the individual monomers in the feed. All the copolymers were completely soluble in polar solvents such as dimethyl sulfoxide and showed higher heat stability as the chloroaniline concentration increased. These effects could be interpreted in terms of extensive hydrogen bonding and interchain linking and, therefore, higher electron delocalization in these copolymers due to the presence of electron‐rich toluidine rings adjacent to electron‐deficient chloroaniline. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1579–1587, 2005     

含苯胺低聚物侧链的导电共聚物的合成与性能研究

通过高分子反应合成了含有不同长度苯胺链段的聚甲基丙烯酸类接枝聚合物 ,研究结果发现 ,当苯胺链段达到一定长度时 ,经质子酸掺杂后的聚合物具有一定的电导性 ,其中 ,接枝苯胺八聚体的共聚物经质子酸掺杂后其电导率可以达到 10 - 5S cm .     

Chemical synthesis and electric properties of the conducting copolymer of aniline and o‐aminophenol

A copolymer, poly(aniline‐co‐o‐aminophenol), was prepared chemically by using ammonium peroxydisulfate as an oxidant. The monomer concentration ratio of o‐aminophenol to aniline strongly influences the copolymerization rate and properties of the copolymer. The optimum composition of a mixture for the chemical copolymerization consisted of 0.3 M aniline, 0.021 M o‐aminophenol, 0.42 M ammonium peroxydisulfate, and 2 M H₂SO₄. The result of cyclic voltammograms in a potential region of ?0.20 to 0.80 V (vs.SCE) indicates that the electrochemical activity of the copolymer prepared under the optimum condition is similar to that of polyaniline in more acid solutions. However, the copolymer still holds the good electrochemical activity until pH 11.0. Therefore, the pH dependence of the electrochemical property of the copolymer is improved, compared with poly(aniline‐co‐o‐aminophenol) prepared electrochemically, and is much better than that of polyaniline. The spectra of IR and ¹H NMR confirm that o‐aminophenol units are included in the copolymer chain, which play a key role in extending the usable pH region of the copolymer. The visible spectra of the copolymers show that a high concentration ratio of o‐aminophenol to aniline in a mixture inhibits the chain growth. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5573–5582, 2007     

固相法合成苯胺与邻甲氧基苯胺共聚物及其性能

以苯胺和邻甲氧基苯胺为单体,甲磺酸为掺杂酸,用固相法合成了甲磺酸掺杂苯胺与邻甲氧基苯胺共聚物。 通过红外光谱、紫外可见吸收光谱、X射线衍射、透射电子显微镜、循环伏安和电导率等对共聚物进行了结构表征和性能测试。 结果表明,不同摩尔比的苯胺与邻甲氧基苯胺共聚物处于中间氧化态,随邻甲氧基苯胺含量的增大,共聚物的掺杂率降低。 共聚物具有较高的结晶性和纤维状形貌,当苯胺与邻甲氧基苯胺摩尔比为1∶1时,具有较高的电化学活性,其导电率为1.65 S/cm。     

Polyaniline and its modification for electroresponsive material under applied electric fields

Polyaniline (PANI) and its various copolymers were synthesized using different monomers such as o‐methyl‐, o‐methoxy‐, o‐ethyl‐, o‐ethoxyaniline and sodium diphenylamine sulfonate by the chemical oxidation polymerization as air‐stable organic conducting polymers, and adopted as one of the most potential materials of electrorheological (ER) fluids, especially for the anhydrous system. A relatively low density, a controllable conductivity, and thermal stability are advantages of the PANI based ER system compared with other ER materials. An FT‐IR analysis was adopted to confirm their synthesis and a scanning electron microscopy (SEM) analysis indicated the shape of PANI derivatives was irregular. The effect of functional group of PANI on electric and electroresponsive properties of poly(aniline‐co‐ethoxyaniline) (COPA) particles were examined. A universal scaling equation of the yield stress was applied to these ER fluids and it was found that all data were collapsed successfully onto a single curve regardless of monomer type of the polyaniline synthesized. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and properties of poly(aniline-co-azidoaniline)

Copolymers of polyaniline and o-azidoaniline were synthesized by chemical oxidative polymerization. The copolymers were characterized by powder X-ray diffraction (XRD) and UV/Vis and FT-IR spectroscopy. Thermal activation of the azido chromophore in the copolymer caused it to react and cross-link into adjacent polymer chains. The cross-linking of the copolymers was indicated by the depletion of the azido band in the FT-IR spectrum. The effects of the cross-linking were studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and four-probe conductivity. The TGA showed that the thermal stability of the copolymers is improved due to cross-linking. However, the increased thermal stability is accompanied by a decrease in electrical conductivity due to the loss of conjugation detected by UV/Vis spectroscopy and a loss of crystallinity due to the azido substituents, which was demonstrated by XRD.     

Spectral,morphological, and antibacterial studies of conducting copolymers,Ppy‐MA,and their nanocomposites,Ag@Ppy‐MA

Pyrrole and methyl anthranilate were copolymerized in different molar ratios in the presence of, H₂O₂, and FeSO₄ at ambient temperature and pressure to obtain efficient conducting copolymers, Ppy‐MA. These conducting copolymers, Ppy‐MA, were in situ reacted with silver nanoparticles to generate nanocomposites, Ag@Ppy‐MA, which exhibit enhanced electrical conductivity. The spectra and morphology of different copolymers, Ppy‐MA, and their nanocomposites, Ag@Ppy‐MA, were analyzed using Fourier transform infrared, SEM, tunneling electron microscopy, X‐ray diffraction, thermogravimetric analysis, and differential thermal analysis. These studies have shown that the nanocomposites, Ag@Ppy‐MA, are thermally more stable and good electrical conductors as compared with their copolymers, Ppy‐MA. The antibacterial activity of the copolymers, Ppy‐MA, prepared from different monomer ratios and their nanocomposites, Ag@Ppy‐MA, has been carried out using disk diffusion method. The copolymers, Ppy‐MA, and its nanocomposites, Ag@Ppy‐MA, were screened against the standard drug Ciprofloxacin. The results clearly suggest that the nanocomposites, Ag@Ppy‐MA, are better antibacterial agent as compared with their copolymers, Ppy‐MA. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and properties of processable conducting copolymers from N‐ethylaniline with aniline

Copolymers were synthesized through the chemically oxidative polymerization of N‐ethylaniline (EA) and aniline (AN) in five acid aqueous media. The polymerization yield, intrinsic viscosity, molecular weight, solubility, solvatochromism, electrical conductivity, and mechanical properties of the copolymer films were systematically studied through changes in the comonomer ratio, polymerization temperature, oxidant, oxidant/monomer ratio, and acid medium. Open‐circuit‐potential and temperature measurements of the polymerization solutions showed that the polymerization rate depended on the EA content, and the polymerization was an exothermic reaction. The resultant copolymers were characterized in detail with IR, ultraviolet–visible, and ¹H NMR spectroscopy, gel permeation chromatography, wide‐angle X‐ray diffractometry, and scanning electron microscopy. The reactivity ratios of the monomer pair were calculated from the ¹H NMR spectra of the copolymers formed at a low conversion. The polymers exhibited good solubility and interesting solvatochromism in most of the solvents and variable conductivity with the EA/AN ratio and doping state. The conductivity of the HCl‐doped copolymers increased monotonically from 5.61 × 10^?7 to 2.55 × 10^?1 S/cm with decreasing EA content from 100 to 0 mol % and showed a percolation transition between EA concentrations of 20 and 30 mol %. The EA/AN copolymers also had excellent film formability and flexibility together with high mechanical and oxygen‐enriching properties. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6109–6124, 2004     

Copolymers and two-layered composites of poly(<Emphasis Type="Italic">o</Emphasis>-aminophenol) and polyaniline

Electroactive conducting copolymers of aniline (ANI) and o-aminophenol (OAP) and two-layered poly(o-aminophenol) (POAP)/polyaniline (PANI) composites were prepared in aqueous acidic solution by electrode potential cycling. Copolymerization was carried out at different feed concentrations of OAP and ANI on a gold electrode. A strong inhibition of electropolymerization was found at a high molar fraction of OAP in the feed. The copolymers showed good adherence on the electrode surface and gave a redox response up to pH=10.0. Two transitions were observed in the in situ conductivities of the copolymers (as with PANI), but the conductivities were lower by 2.5–3 orders of magnitude as compared to PANI. Electrosynthesis of PANI on POAP modified electrodes showed copolymer formation after reaction initiation and finally formation of a PANI layer at the copolymer/solution interface. The ‘memory effect’ of the bilayer structures of both polymers was discussed in terms of protonation/deprotonation and anion consumption taking place during redox processes of both polymers.     

Synthesis and characterization of C60/polyaniline composites from interfacial polymerization

C₆₀/polyaniline (PANI) nanocomposites have been synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in the presence of C₆₀ by using an interfacial reaction. When compared with the pure PANI nanofibers from the similar process, the diameter of the obtained C₆₀/PANI nanofibers was increased because of the encapsulation of C₆₀ into PANI during aniline polymerization, which resulted from the charge‐transfer interactions between C₆₀ and aniline fragment in PANI. In addition, the resulting C₆₀/PANI nanocomposites synthesized from the low initial C₆₀/aniline molar ratio (less than 1:25) showed the homogenous morphology composed of fiber network structures, which has an electrical conductivity as high as 1.1 × 10^?4 S/cm. However, the C₆₀/PANI nanocomposites from the higher initial C₆₀/aniline molar ratio (more than 1:15) showed the nonuniformly distributed morphology, and the electrical conductivity was decreased to 3.5 × 10^?5 S/cm. Moreover, the C₆₀/PANI nanocomposites from the interfacial reaction showed a higher value of electrical conductivity than the mechanically mixed C₆₀/PANI blends with the same C₆₀ content, because of the more evenly distributed microstructures. FTIR, UV–vis, and CV data confirmed the presence of C₆₀ and the significant charge‐transfer interactions in the resultant nanocomposites, which was responsible for the morphology development of the C₆₀/PANI and the variation of the electrical conductivity. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Chemical synthesis, spectral characterization and stability of some electrically conducting polymers

<正>The synthesis,characterization,thermal degradation and stability of polyaniline(PANI),poly(m-nitroaniline), poly(m-chloroaniline) and poly(o-methylaniline) were reported.Different properties were measured and compared with PANI to find out the effect of electron donating groups(-CH_3) and electron withdrawing groups(-Cl,- NO_2).It was found that the presence of any type of substitution in the benzene ring of aniline increased the solubility but reduced the yield,thermal stability and electrical conductivity.Two probe methods were used to measure the electrical conductivity of these polymers.The structural properties of these polymers were characterized by using FTIR and UV-Vis spectroscopic methods.Thermal degradation and stability of these polymers were explained by using thermogravimetric analysis(TGA) and conductivity measurements.