Highly conducting free-standing poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) films with improved thermoelectric performances

Highly conducting free-standing poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) films with room-temperature electrical conductivity of about 300 S cm^?1 were successfully prepared from PEDOT/PSS solution containing additives (DMSO or EG) on the smooth and flexible polypropylene (PP) film substrate with contact angle of 87°. As formed free-standing PEDOT/PSS films possess good flexibility and can be easily cut into various shapes with a knife. The contact angle of substrate has significant effect on the preparation of free-standing PEDOT/PSS films. Additionally, the process of adding DMSO or EG did not result in the change of carrier concentration but the increase of carrier mobility. The free-standing PEDOT/PSS film showed high electrical conductivity and stable Seebeck coefficient and its figure of merit (ZT) with high environment stability can be up to 10^?2, one order of magnitude higher than that of pressed PEDOT/PSS pellets (10^?3).     

One-step fabrication of conductive poly(3,4-ethylenedioxythiophene) hollow spheres in the presence of poly(vinylpyrrolidone)

Poly(3,4-ethylenedioxythiophene) (PEDOT) hollow spheres with the size ranged from 130 to 820 nm and a conductivity of 8 × 10^?2 S cm^?1 were prepared simply and directly via a one-step self-assembly approach in the presence of poly(vinylpyrrolidone) (PVP) as a soft template. It was found that the formation probability of PEDOT hollow spheres depended on the concentration of PVP. Bulk quantities of PEDOT hollow spheres can be obtained readily under the optimal conditions such as the concentration of PVP > 0.175 mM and PVP/EDOT molar ratio <1.4. The electron-rich oxygen atoms on the lactam groups in PVP were proposed to act as the chemically active sites to anchor EDOT cation radicals by virtue of electrostatic interaction and cause the self-assembly of PEDOT hollow spheres. Our investigation for the formation mechanism of PEDOT hollow spheres may shed some light on preparing of other hollow materials by proper molecular design and experimental condition optimization.     

Spectroscopic and conductivity studies of doping in chemically synthesized poly(3,4-ethylenedioxythiophene)

Spectroscopic methods (Raman (514.5 nm excitation), infrared (IR), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR)) and electrical conductivity measurements were used to characterize the electrically conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) prepared by persulfate oxidation under aqueous conditions. Elemental analysis was carried out on the resulting sulfate-doped PEDOT to determine the sulfate doping level. Due to the difficulty in dedoping highly stable p-doped PEDOT, the sulfate-pre-doped PEDOT was directly treated with iodine solution in order to investigate the secondary doping processes between PEDOT and iodine. Two processes were observed: (1) the further oxidation of the polymer by iodine to produce an increase in the doping level, with triiodide as the dopant and (2) the replacement of sulfate by triiodide in an ion-exchange process involving triiodide in equilibrium with iodine in the iodine solution. Conductivity studies, in conjunction with XPS and EPR experiments, were used to analyse the relationship between the doping level and conductivity that was explained by differences in the nature of SO₄²⁻ and I₃⁻ as dopant ions and a shift in the polaron/bipolaron equilibrium. The Raman spectra (785 nm excitation) of these PEDOT samples were also investigated and a significant change has been observed in the wavenumber of the symmetric C_α = C_β stretching bands with varying levels of dopants. A correlation was observed between the ratio of the integrated intensities of the symmetric C_α = C_β stretching bands and the doping level in PEDOT that can be useful for estimating the doping level of a PEDOT sample from its Raman spectrum.     

PEDOT/PAMPS: An electrically conductive polymer composite with electrochromic and cation exchange properties

Poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(2-acrylamido-2-methyl-l-propane sulfonate) (PAMPS) composite films were electrochemically prepared from a mixture of water and N,N-dimethylformamide (DMF) containing 3,4-ethylenedioxythiophene (EDOT) and the polyelectrolyte, PAMPS. The presence of PAMPS in the PEDOT matrix was confirmed by spectroscopic and electrochemical methods. Depending on the current density, the conductivity of PEDOT/PAMPS free standing composite films reached values of 80 S/cm. Spectroelectrochemistry of neutralized PEDOT/PAMPS composite films showed a maximum absorption at 2.0 eV (615 nm) and a band gap of 1.65 eV, as calculated from the onset of the π–π* transition. Thin PEDOT/PAMPS composite films were found to switch rapidly between oxidized and reduced states in less than 0.4 s with an initial optical contrast of 76% at λ_max: 615 nm. The morphology of the polymer composites demonstrates a cauliflower structure. Despite the high molecular weight of the polyelectrolyte, the film density was found to be similar to classical PEDOT (i.e., ca. 1.4 g/cm³), while the surface roughness averaged below 5%. As expected with the use of a sulfonated polyelectrolyte as dopant, cation exchange properties were observed with hexaammineruthenium(III) chloride as an active electrolyte.     

Structure and properties of solid-state synthesized poly(3′,4′-ethylenedioxy-2,2′:5′,2″-terthiophene)

A polyterthiophene derivative: poly(3′,4′-ethylenedioxy-2,2′:5′,2″-terthiophene) was synthesized by solid-state oxidative-polymerization of 3′,4′-ethylenedioxy-2,2′:5′,2″-terthiophene (TET) in various ratios of oxidant (FeCl₃) to the monomer (TET). The resulting polymers were characterized by FT-IR, ¹H NMR, TEM, SEM, UV–vis–NIR, GPC, X-ray diffraction, EDX, CV, galvanostatic charge–discharge, as well as TGA and conductivity measurements. The results showed that the as-made poly(TET)s were partially in doped state with a conductivity ranging from 2.1 × 10^?3 S cm^?1 to 8.1 × 10^?3 S cm^?1 at room temperature, and exhibited good thermal stability in nitrogen up to 337–356 °C. The poly(TET)s showed a similar UV–vis absorption peak at 462 nm in acetonitrile. In addition, as-made poly(TET)s had low molecular weight ranging from 3300 to 3500 with microstructured morphology including nanorodes and nanofibers, and presented one redox couple at 1.1–1.2 V(ox) and 0.6–0.7 V(re) in 0.1 M Et₄NBF₄ acetonitrile solution. A moderate specific capacitance of 71 F g^?1 for poly(TET) modified graft electrode was obtained within the potential range of ?0.2 V to 0.5 V in 1 M H₂SO₄ solution. X-ray diffraction results imply the enhanced crystallinity of poly(TET)s, indicating the existence of crystalline phase in polymer matrix. Furthermore, the comparison of results from every measurement indicated that the [FeCl₃]/[TET] ratio strongly affects the morphology of the poly(TET), and the fibrillar growth tendency of poly(TET) was observed with the increase of the [FeCl₃]/[TET] ratio, and long-length fibrillar morphology occurred in the highest [FeCl₃]/[TET] ratio.     

Functional electrospun nanofibres of poly(lactic acid) blends with polyaniline or poly(aniline-co-benzoic acid)

Functionalised nanofibres of a controlled fibre diameter were electrospun from solutions of polyaniline (PANI) or poly(aniline-co-m-aminobenzoic acid) (P(ANI-co-m-ABA)) with poly(lactic acid) (PLA). Soluble copolymers of aniline (ANI) and m-aminobenzoic acid (m-ABA) were prepared and the average molecular weight of the copolymers, as determined by gel permeation chromatography, was found to decrease from 13,800 g mol^?1 to 1640 g mol^?1 with an increase of m-ABA content in the copolymer. By contrast, FT-MS results revealed that homopolymerisation of m-ABA formed oligomers rather than polymeric chains due to low reactivity of m-ABA monomer. ATR FTIR, Raman spectroscopy, and conductivity measurements confirmed incorporation of the conducting (co)polymers within the PLA based nanofibres. The conductivity of the nanofibres increased significantly with increased proportion of PANI or P(ANI-co-m-ABA) to 2.0 × 10^?5 mS cm^?1 for PLA/PANI (3.27% of PANI) and 8.3 × 10^?6 mS cm^?1 for PLA/P(ANI-co-m-ABA) (5.80% of the copolymer in the blend). The nanofibre diameter decreased from 640 ± 195 nm for pure PLA fibres to 141 ± 68 nm for PLA/PANI, and to 124 ± 31 nm for PLA/P(ANI-co-m-ABA). These fibres have potential for a range of applications, such as electroactive scaffold tissue engineering and sensing.     

One-pot synthesis of highly stable silver nanoparticles-conducting polymer nanocomposite and its catalytic application

Herein, we report the preparation of highly stable Ag_nano–PEDOT nanocomposite by one-pot fashion in acidic condition using 3,4-ethylenedioxythiophene (EDOT) as a reductant and polystyrene sulfonate (PSS^?) as a dopant for PEDOT as well as particle stabilizer for silver nanoparticles (AgNPs). The above nanocomposite denoted as Ag_nano–PEDOT/PSS^? nanocomposite. The formation of AgNPs with concomitant EDOT oxidation was followed by UV–visible (UV–vis) spectroscopy at different time intervals. Ag_nano–PEDOT/PSS^? nanocomposite shows absorption bands at 380 and above 700 nm, which correspond to surface plasmon resonance (SPR) peak of AgNPs and oxidized PEDOT, respectively. Ag_nano–PEDOT/PSS^? nanocomposite was characterized by infrared (IR) spectroscopy, transmission electron microscopy (TEM), and XRD. TEM study reveals that AgNPs are distributed uniformly around PEDOT polymer with an average particle size diameter of 10–15 nm. In addition, Ag_nano–PEDOT/PSS^? nanocomposite was tested for the catalytic reduction of 4-nitrophenol. For comparing stability, we were also synthesized AgNPs in the absence of PSS^? (denoted as Ag_nano–PEDOT) using EDOT as reductant. UV–vis spectrum of Ag_nano–PEDOT nanocomposite revealed that AgNPs prepared in the absence of PSS^? was not stable.     

Effect of various parameters on the conductivity of free standing electrosynthesized polypyrrole films

Electrical characteristics of polypyrrole films electrodeposited in different aqueous electrolyte solutions including p-toluenesulfonate, naphtalenesulfonate, nitrate, tetrafluoroborate, and perchlorate anions were investigated using the Van der Pauw procedure. The polymer films were synthesized by electrochemical oxidation at a fixed potential. Experimental parameters including the pyrrole concentration, electrolyte, applied potential and substrate were shown to affect the electrical conductivity σ of polypyrrole films. Since the substrate contributes significantly to the overall conductivity of polypyrrole-coated electrodes, the results obtained with free standing polymer films appeared more reliable. The results indicated that the p-toluenesulfonate doped PPy film showed the highest average conductivity (σ_293 K = 4.5 × 10⁵ S m^?1) whereas the perchlorate doped one produced the lowest of all the films prepared (σ_293 K = 2 × 10⁴ S m^?1).     

Photoinduced protonation of polyaniline assisted by hydrogen-bonding materials

Composites of the emeraldine base form of polyaniline (PANI-EB) and photo-acid generators (PAGs) increase their conductivities upon photo-irradiation due to protonation of PANI-EB. Such materials may be utilized to fabricate conducting patterns by photo-irradiation. However, the conductivity obtained by direct irradiation of PANI-EB/PAG composites was normally quite low, and conductivity above 10^?3 S cm^?1 often required post-treatment with HCl. In this work, poly(vinyl alcohol) (PVA), which can form a hydrogen bonding network, was added to PANI-EB/PAG. Results showed that PVA enhanced film quality, conductivity and reproducibility. Photo-induced conductivity of 10^?2 S cm^?1 was obtained when the ratio of PANI-EB/PVA/PAG was 1:1:0.6. A novel PAG, bis(p-hydroxyphenyl)phenylsulfoniumtriflate [(PhOH)₂PhS⁺ OTf^?], which can form hydrogen bonds with PANI was synthesized and mixed with PANI-EB. A composite of PANI-EB and the PAG with a ratio of 1:0.5 achieved a conductivity of 10^?1 S cm^?1 after irradiation. However, the initial conductivity before irradiation was as high as 10^?5 S cm^?1 due to relatively high acidity of the PAG.     

Ionic liquid doped poly(N-methyl 4-vinylpyridine iodide) solid polymer electrolyte for dye-sensitized solar cell

Ion conducting polymer electrolyte, poly(N-methyl 4-vinylpyridine iodide) (PVPI) is synthesized for dye-sensitized solar cell (DSSC) application. A new solid polymer electrolyte composite containing low viscosity ionic liquid (IL) 1-ethyl 3-methylimidazolium dicyanamide (EMImDCN) doped PVPI is developed and its structural, electrical and photoelectrochemical studies are presented in detail. Fourier transform infrared (FTIR) spectroscopy, proton NMR and atomic force microscopy (AFM) affirms the modified polymer and its composite nature with porous surface morphology. The developed solid polymer electrolyte shows enhancement in ionic conductivity (σ) due to IL doping. The maximum σ value of 9.12 × 10^?6 S cm^?1 was obtained at 40 wt% IL concentration. The redox behavior of the electrolyte has been verified by the cyclic voltammetry studies. For device application, we have fabricated a DSSC using this solid polymer–IL electrolyte system which shows energy conversion efficiency of the solid-state cell as 0.65% under irradiation of simulated sunlight (AM 1.5, 100 mW cm^?2).     

Alkali doped poly(vinyl alcohol) for potential fuel cell applications

Optical transparent, chemically stable alkaline solid polymer electrolyte membranes were prepared by incorporation KOH in poly(vinyl alcohol) (PVA). The distributions of oxygen and potassium in the membrane were characterized by XRD and SEM–EDX. It is demonstrated that combined KOH molecules may exist in the PVA matrix, which allow it to be an ionic conductor. In particular, the chemical and thermal stabilities were investigated by measuring changes of ionic conductivities after conditioned the membrane in various alkaline concentrations at elevated temperatures for 24 h for potential use in fuel cells. The membranes were found very stable even in 10 M KOH solution up to 80 °C without losing any membrane integrity and ionic conductivity due to high dense chemical cross-linking in PVA structure. The measured ionic conductivity of the membrane by AC impedance technique ranged from 2.75 × 10^?4 S cm^?1 to 4.73 × 10^?4 S cm^?1 at room temperature, which was greatly increased to 9.77 × 10^?4 S cm^?1 after high temperature conditioning at 80 °C. Although, a relatively higher water uptake, the methanol uptake of this membrane was one-half of Nafon 115 at room temperature and 6 times lower than that of Nafion 115 after conditioned at 80 °C. The membrane electrolyte assembly (MEA) fabricated with PVA–KOH in direct methanol fuel cell (DMFC) mode showed an initial power density of 6.04 mW cm^?2 at 60 °C and increased to 10.21 mW cm^?2 at 90 °C.     

Crystal structure and physical properties of a magnetic molecular conductor (EDO-TTFVODS)2FeCl4

Crystal structure, and electrical conducting and magnetic properties of a radical cation salt of EDO-TTFVODS with magnetic FeCl₄^? ion, (EDO-TTFVODS)₂FeCl₄ (EDO-TTFVODS = ethylenedioxytetrathiafulvalenoquinone-1,3-diselenolemethide) are reported. In this salt, there are two independent donor molecules formed two different layers A and B, and the counter FeCl₄^? ions layer is sandwiched between two donor layers A and B along the b-axis. The donor molecules form the one-dimensional columns along the a-axis in both donor layers. This salt shows high conductivity at room temperature (σ_RT = 25 S cm^?1) and a metallic behavior down to ca. 80 K, where a metal–insulator transition however occurs. The magnetic susceptibility obeys a Curie–Weiss law (Curie constant C = 4.42 emu K mol^?1 and Weiss temperature Θ = ?1.5 K), without any magnetic ordering down to 1.8 K. This result suggests the weak antiferromagnetic interaction between the d spins of FeCl₄^? ions.     

High thermoelectric performance of poly(2,5-dimethoxyphenylenevinylene) and its derivatives

Poly(2,5-dimethoxyphenylenevinylene) (PMeOPV) and a series of copolymers consisting of both 2,5-dimethoxy-substituted phenylenevinylene units and unsubstituted units (P(MeOPV-co-PV)) were evaluated from the viewpoint of their thermoelectric properties. Their conjugated polymer films were prepared by pyrolysis of stretched or unstretched films of sulfonium salt precursor polymers, and subsequently doped with iodine vapor to provide electrical conductivity. The power factors P (=S²σ), indicating thermoelectric performance, were calculated with the measured electrical conductivity σ and Seebeck coefficient S of the doped films. PMeOPV showed a higher power factor of 7.1 μW m⁻¹ K⁻² at 313 K than that of a camphorsulfonic acid-doped polyaniline as reference. P(MeOPV-co-PV) precursor polymers with less than 20 mol% of MeOPV unit content in the monomer feed were stretchable, therefore providing stretched P(MeOPV-co-PV) films with low MeOPV unit content. The stretching treatment for P(MeOPV-co-PV) enhanced its electrical conductivity, but kept the Seebeck coefficient at nearly the same level as that of unstretched polymers. Consequently a 4.4-fold stretched copolymer exhibited an electrical conductivity of 183.5 S/cm and a Seebeck coefficient of 43.5 μV/K at 313 K, and thus, its power factor at 313 K was over 30 μW m⁻¹ K⁻². To the best of our knowledge, this is the highest thermoelectric performance ever reported among conducting polymers.     

A comparative investigation between poly(1-ethynylpyrene) and poly(1,6-(3-ethynylpyrenylene)): Influence of the structure on the thermal,optical, electrochemical properties and conductivity

A comparative investigation between trans-poly(1-ethynylpyrene) (trans-PEP) obtained chemically and poly(1,6-(3-ethynylpyrenylene) (E-PEP) prepared electrochemically was carried out. Thermal and optical properties of the polymers were studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and absorption spectroscopy. Electrochemical properties were evaluated by cyclic voltamperometry, in a 0.1 M Et₄NClO₄/THF solution at 10 mV/s, using a Pt disc as working electrode and Ag/AgCl as reference electrode. On the other hand, the conductivity of both polymers was measured in pressed pellet. Trans-PEP (T₁₀ = 369 °C) showed a higher thermal stability than its homologue E-PEP (T₁₀ = 256 °C). DSC of the polymers showed that trans-PEP exhibits a softening point at 330 °C, whereas E-PEP does it at 117 °C. Absorption spectra of the polymers revealed that trans-PEP exhibits two absorption bands at λ = 336 nm and λ = 580 nm due to the pyrene moieties and the highly conjugated polyacetylene main chain, respectively. By contrast, E-PEP showed only an absorption band at λ = 358 nm followed by a tail, which reveals that this polymer possesses a lower degree of conjugation. Molecular modelling performed in short segments of these polymers confirmed this hypothesis. Regarding the electrochemical properties, trans-PEP showed an anodic peak at 1500 mV and a conductivity value σ = 2.7 × 10^?2 S/cm, whereas E-PEP exhibited an anodic oxidation peak at 1670 mV and σ = 8.4 × 10^?2 S/cm.     

Synthesis,characterization and magnetic properties of polyaniline-magnetite nanocomposites

In this work we report a new and straightforward method to prepare the polyaniline-magnetite nanocomposite PANI-Fe₃O₄. The method utilizes Fe₃O₄ nanoparticles as the oxidizing agent assisted by UV light to synthesize PANI-Fe₃O₄ magnetic nanocomposite. FTIR and XRD analyses confirm that polyaniline has been obtained in the emeraldine salt form and that the mean diameter of the Fe₃O₄ nanoparticles before synthesis was of the order of 25 nm; for the PANI-Fe₃O₄ nanocomposite in HCl after 4 h of reaction, the mean diameters were of the order of 11 nm. Also, feroxyhite was detected as a secondary phase for the nanocomposite. The dc conductivity results for the pure magnetite were about 2.4 × 10^?6 S cm^?1, while the nanocomposites were of the order of 10^?5 S cm^?1, confirming the increase in conductivity with the increasing amount of PANI. The magnetic measurements showed ferromagnetic behavior for the nanoparticles, with high-saturated magnetization (M_S = 74.30 emu g^?1) and a coercive force of 93.40 Oe. In addition, it was observed that the saturated magnetization for the nanocomposite strongly depends on the reaction time under UV irradiation.     

Fabrication and catalytic property of an Ag@poly(3,4-ethylenedioxythiophene) yolk/shell structure

Poly(3,4-ethylenedioxythiophene) (PEDOT) hollow spheres with the size ranged from 210 to 850 nm and a conductivity of 6 × 10^?2 S cm^?1 have been prepared via electrochemical polymerization of 3,4-ethylenedioxythiophene in the presence of poly(vinyl pyrrolidone) as a soft template. Then, a novel Ag@PEDOT yolk/shell structure has been prepared simply and directly by a penetration and reduction approach. The morphology, formation, and the catalytic activity of the as-prepared Ag@PEDOT yolk/shell structure have been investigated. The experimental result shows that the as-prepared Ag@PEDOT yolk/shell structure exhibits excellent catalytic activity on reduction of p-nitrophenol. The employed approach may shed some light on preparing other noble metal@conductive polymer core/shell structure.     

Effects of iron(III) p-toluenesulfonate hexahydrate oxidant on the growth of conductive poly(3,4-ethylenedioxythiophene) (PEDOT) nanofilms by vapor phase polymerization

Study of the effects of evaporation time and oxidant concentration on the polymerization rate and final thickness of poly(3,4-ethylenedioxythiophene) (PEDOT) films found that the polymerization was chemical reaction limited, and that the final film thickness was linearly dependent on oxidant concentration. The influence of spin-coated iron(III) p-toluenesulfonate hexahydrate (Fe(PTS)₃) oxidant solution on the polymerization and resulting PEDOT structures was also investigated. Spin-coated low-density (1.35 g/cm³) Fe(PTS)₃ oxidant solution, consisting of highly anisotropic paracystalline structures, provided open frameworks for the growth of conducting polymers, leading to a-axis oriented paracrystalline PEDOT films. Polymerization proceeded through the oxidant framework, increasing the density of PEDOT-filled oxidant solution to 2.01 g/cm³ with negligible change of thickness. Furthermore, the formation of a surface organic layer, as a result of spinning, promoted uniform and smooth PEDOT films.     

Composites of low bandgap conducting polymer-wrapped MWNT and poly(methyl methacrylate) for low percolation and high transparency

The composites of multi-walled carbon nanotubes (MWNT) wrapped with low bandgap conjugated polymer and poly(methyl methacrylate) (PMMA) were prepared for transparent conductive films. NIR-absorbing poly(ethyl thieno[3,4-b]thiophene-2-carboxylate) (PTTEt) with E_g of 1.0 eV was used in this study. Upon hybridization with MWNT, PTTEt in an insulating state became partially conductive due to electron transfer from PTTEt to MWNT, meaning that PTTEt can function as conductive glue interconnecting MWNT in a PMMA matrix. The electrical conduction of the composites (PTTEt-MWNT/PMMA), consisting of PTTEt-wrapped MWNT (PTTEt-MWNT/PMMA) and PMMA, showed the percolation at 0.10 wt% MWNT loading, which was ca. 0.18 wt% lower than the composites of MWNT and PMMA (MWNT/PMMA). The maximum conductivity of PTTEt-MWNT/PMMA, on the other hand, was one order of magnitude lower than that of MWNT/PMMA, suggesting that PTTEt incorporation onto MWNT for transparent conductive films is effective within a specific range of MWNT loadings (i.e., between percolation thresholds of MWNT/PMMA and PTTEt–MWNT/PMMA). The comparison of transmittance of PTTEt–MWNT/PMMA (0.18 wt% MWNT) with MWNT/PMMA (0.32 wt% MWNT), possessing the same conductivities (3 × 10^?3 S cm^?1), showed ca. 10% enhanced transmittance at 550 nm. These results imply that hybridization of low bandgap conjugated polymers with carbon nanotubes can be utilized for the reduction of percolation threshold and the increase of optical transparency without sacrificing conductivities at low MWNT loadings.     

Ex situ XANES,XPS and Raman studies of poly(3,4-ethylenedioxythiophene) modified by iron hexacyanoferrate

X-ray (XPS and XANES) and Raman spectra of poly(3,4-ethylenedioxythiophene) (pEDOT) modified by iron hexacyanoferrate (Fehcf) network are presented. XANES studies allowed to postulate an octahedral surrounding of iron atoms in the material and identified nitrogen and carbon atoms as nearest neighbourhoods. XPS measurements reveal iron–nitrogen and iron–carbon bonds, supporting the XANES results. Chemical interaction between sulphur from pEDOT and iron was also evidenced by XPS. Although both methods give proof of Prussian Blue structure inside the polymer, Raman studies did not show any signal typical for CN at about 2160 cm^?1 (ν). However, the presence of Fehcf was confirmed by the stretching vibrations of Fe–N bond at 146 cm^?1 and Fe–CN vibrations at 270 cm^?1. AFM imaging was performed to illustrate the roughness and morphology of the pEDOT/Fehcf surface.     

Polypyrrole and polyaniline prepared with cerium(IV) sulfate oxidant

The conducting polymers, polypyrrole and polyaniline, were synthesized by chemical oxidative polymerization of the corresponding monomers in 0.1 M sulfuric acid using cerium(IV) sulfate as the oxidant at mole ratios of oxidant-to-monomer ranging from 0.5 to 3. The yields of the oxidation products were determined, and the samples were characterized with respect to their elemental composition, molecular structure, and morphology. The conductivity of polypyrrole prepared in 0.1 M sulfuric acid, 10^?1 to 10⁰ S cm^?1, was higher compared with the conductivity of polyaniline prepared under the same conditions, 10^?3 to 10^?1 S cm^?1. The loss of mass after deprotonation with ammonium hydroxide is reported, and discussed in terms of the type of protonation as also reflected by FTIR spectroscopy. The conductivity of polypyrrole bases remained at relatively high level, 10^?5 to 10^?3 S cm^?1, while PANI bases became non-conducting, 10^?12 to 10^?10 S cm^?1. The polymers had a granular morphology in all cases.