Large‐scale synthesis of polyaniline nanofibers based on renewable resource molecular template

We report reproducible large‐scale synthesis of polyaniline (PANI) nanofibers up to 100 g scale via micelle mediated soft template approach. A unique built‐in amphiphilic azobenzenesulfonic acid based on renewable resource dopant was synthesized for large‐scale production of PANI nanofibres. The amphiphilic surfactant exists as 4.3 nm micelle in water and it self‐organized with aniline to form long cylindrical aggregates, which template for PANI nanofibers. The PANI nanofibers were found soluble in water and organic solvents and they were characterized by ¹H‐NMR, FT‐IR, and viscosity techniques. The mechanism of the PANI nanofiber formation was investigated by dynamic light scattering, scanning electron microscopy, and high resolution transmission electron microscopy. The width of the nanofibers was precisely controlled from 130–200 nm with length up to ～ 5 μm. The absorption spectroscopic analysis of nanofibers in water revealed that the large‐scale samples (10, 50, and 100 g) were found to posses expanded chain conformation compared to that of 1 g scale sample. The wide angle X‐ray diffraction patterns showed two new peaks at lower angles at d spacing of 25.5 and 13.6 Å corresponding to lamellar ordering of PANI chains followed by interdigitation of the amphiphilic dopant in the nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Fabrication and microwave absorption properties of BaTiO3 nanotube/polyaniline hybrid nanomaterials

Hybrid nanomaterials consisting of BaTiO₃ nanotubes (BTO NTs) and polyaniline (PANI), hereafter denoted as BTO NT/PANI, were successfully prepared by a one‐step in situ oxidative polymerization process of aniline monomers in the presence of BaTiO₃ nanotubes, with ammonium persulfate as oxidant and hydrochloric acid as dopant. The structure and morphology of the nanocomposites were characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray powder diffraction, thermogravimetric analysis, and X‐ray photoelectron spectroscopy. The conductivity property of the hybrid nanomaterials was also investigated. Compared with pure polyaniline, BTO NT/PANI hybrid nanomaterials exhibited enhanced reflection loss properties, which can even be further improved with appropriate electromagnetic impedance matching. More importantly, microwave‐absorbing properties of the nanocomposites can be simply modulated simply by controlling the BaTiO₃ NTs content of the absorber for the required frequency bands. Therefore, these composites may be used as lightweight andhighly effective microwave absorbers. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers     

Ferromagnetic polyaniline/TiO2 nanocomposites

Novel ferromagnetic semiconducting polyaniline PANI/TiO₂ nanocomposites were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium, in the presence of colloidal TiO₂ nanoparticles (d ∼ 4.5 nm), without added acid. The morphological, magnetic, structural, and optical properties of the PANI/TiO₂ nanocomposites prepared at initial aniline/TiO₂ mole ratios 80, 40, and 20 were studied by scanning electron microscopy, superconducting quantum interference device, X‐ray powder diffraction, FTIR, Raman, and UV‐Vis spectroscopies. The emeraldine salt form of linear PANI chains as well as the presence of phenazine units, branched PANI chains, and anatase crystalline structure of TiO₂ in PANI/TiO₂ nanocomposites was confirmed by FTIR and Raman spectroscopies. The electrical conductivity of synthesized composites was ∼10⁻³ S cm⁻¹. The room temperature ferromagnetic response with coercive field of H_c ∼ 300 Oe and the remanent magnetization of M_r ∼ 4.35 × 10⁻⁴ emu/g was detected in all investigated PANI/TiO₂ nanocomposites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Intercalated polyaniline–kaolinite nanocomposite prepared via in situ mechanochemical synthesis

The in situ polymerization of aniline monomers within kaolinite interlayers easily led to an intercalated polyaniline (PANI)–kaolinite nanocomposite through a facile mechanochemical method. The X‐ray diffraction results demonstrate that PANI was successfully intercalated in the interlayers of kaolinite, which was lightened by an increased basal spacing from 7.24 to 14.67 Å of kaolinite in the as‐synthesized nanocomposite, and the characterization results from Fourier transform infrared spectrometry, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy further confirm this conclusion. The thermal stability of PANI was improved significantly when PANI was intercalated into kaolinite to form the nanocomposite; this was proven by thermogravimetric analysis. Moreover, a panel experiment was carried out under a simulated marine environment to evaluate the anticorrosive effect of the as‐prepared product, and the results show that the epoxy resin/intercalated PANI–kaolinite nanocomposite coating had a better anticorrosive effect than that of the neat epoxy resin coating. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43551.     

Characterization and conductivity studies of nanocomposite films with polymer networks containing polyaniline‐alginate/titanium dioxide

Polyaniline nanocomposite films were chemically synthesized in the presence of alginate template by varying the concentration of TiO₂ in the composites. Characterization of the composite samples by FTIR, UV‐Vis spectra (UV), and X‐ray diffraction (XRD) indicates the formation of polyaniline‐alginate/titanium dioxide (PAT) composites. The morphology analysis by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) also supports the formation of the composites. Temperature‐dependent DC conductivity of the polyaniline‐alginate (PA) and PAT composites was studied in the range of 300 ≤ T ≤ 500 K. UV‐Vis and FTIR spectral studies reveal that the alginate is a good template for the chemical interaction between polyaniline and TiO₂, which suggests that the micelles formed by the anilinium‐alginate cations containing TiO₂ are responsible for the transport properties of the PAT composites. POLYM. COMPOS., 31:1754–1761, 2010. © 2010 Society of Plastics Engineers.     

Polyaniline–organoclay nanocomposites as curing agent for epoxy: Preparation and characterization

Polyaniline (PANI)–organoclay/Epoxy (EP) nanocomposites were prepared. PANI–organoclay nanocomposites were used as curing agent for EP. Organoclay was prepared by an ion exchange process between sodium cations in MMT and NH₃⁺ groups in polyoxypropylene (D₂₃₀). PANI–organoclay nanocomposite was synthesized by in situ polymerization of aniline in (14 wt%) organoclay. Infrared spectra and differential scanning calorimetry confirm the curing of EP. The absence of d₀₀₁ diffraction band of organoclay in the nanocomposites was observed by X‐ray diffraction. The structure argument was further supported by scanning electron microscopy and transmission electron microscopy. Electrical conductivity of the nanocomposites within the range 2.1 × 10⁻⁷–3.2 × 10⁻⁷ S/cm depending on the concentration of the PANI/D₂₃₀‐MMT. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Preparation of polystyrene/clay nanocomposite by suspension and emulsion polymerization

Organophilic montmorillonite was prepared using ion‐exchange method between sodium ions in clay layers and four kind of quaternary ammonium salt. The montmorillonite has the largest d₀₀₁‐spacing, as determined by X‐ray diffraction in modified by di(hydrogenated tallowalkyl) dimethyl ammonium chloride. Polystyrene montmorillonite nanocomposites were obtained by suspension and emulsion polymerization of styrene in the dispersed organophilic montmorillonite. The d₀₀₁‐spacing of clay was determined by X‐ray diffraction (XRD). The thermal stability of organophilic montmorillonite was investigated by thermogravimetric analysis (TGA). POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Controllable synthesis and characterization of poly(aniline‐co‐pyrrole) using anionic spherical polyelectrolyte brushes as dopant and template

A poly(aniline‐co‐pyrrole), using anionic spherical polyelectrolyte brushes (ASPB) as dopant and template, was synthesized by chemical oxidation polymerization. The composites were characterized by scanning electron microscopy (SEM), Fourier‐transform infrared spectrometry (FTIR), X‐ray diffraction (XRD), and electrical studies. The SEM images confirmed that the composites had a spherical‐like structure, with a size of ca. 170 nm. The FTIR spectra showed the intermolecular interaction between poly(aniline‐co‐pyrrole) and ASPB. The XRD analysis revealed that the interplanar distance of the copolymers increased from 0.373 nm to 0.391 nm. The electrical conductivity of the poly(aniline‐co‐pyrrole)/ASPB nanocomposites at room temperature was 8.3 S cm⁻¹, higher than that of the conducting copolymers (2.1 S cm⁻¹). These conductive nanocomposites have nanoparticle size, controllable morphology, and the potential for application in inkjet electronic printing. POLYM. COMPOS., 35:1858–1863, 2014. © 2014 Society of Plastics Engineers     

Silica–polyaniline hybrid materials prepared by inverse emulsion polymerization for epoxy‐based anticorrosive coating

Polyaniline doped with dodecylbenzene sulfonic acid (PAni.DBSA) was prepared by inverse emulsion polymerization of aniline in toluene medium in the presence of silica (SiO₂) nanoparticles. The presence of cetyltrimethylammonium bromide (CTAB) during the aniline polymerization results in hybrid material with smaller particle size, as indicated by dynamic light scattering analysis and scanning electron microscopy. Also the electrical conductivity of such hybrid is one order higher, as compared with that prepared without CTAB. Moreover, more ordered PAni chain is obtained as indicated by the red shift of the π–polaron transition band observed by UV–vis spectroscopy and higher crystallinity observed by X‐ray diffraction analysis. Anti‐corrosive properties of carbon steel substrate coated with epoxy resin containing 5 wt % of PAni.DBSA and the corresponding SiO₂‐based hybrid materials were evaluated in 3.5% NaCl solution by electrochemical impedance spectroscopy. The coating resistance increases by one order for the epoxy system containing PAni.DBSA/SiO₂ hybrid prepared in the presence of CTAB, thus confirming the anticorrosion efficiency of this hybrid. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45505.     

Synthesis and characterization of polyaniline–organoclay nanocomposites

Polyaniline (PANI)–organoclay nanocomposites were prepared. Intercalation of aniline monomer into montmorillonite (MMT) modified by polyoxyalkylene was followed by subsequent oxidative polymerization of the aniline in the interlayer spacing. The organoclay was prepared by cation exchange process between sodium cation in MMT and onium ion in four different types of polyoxyalkylene diamine and triamine with different molecular weight. Infrared spectra confirm the electrostatic interaction between the positively charged onium group (NH₃⁺) and the negatively charged surface of MMT. X‐ray diffraction analysis provides a structural information. The absence of d₀₀₁ diffraction band in the nanocomposites was observed at certain types and contents of organoclay. Scanning electron microscopy and transmission electron microscopy were employed to determine the dispersion of the clay into PANI. The thermal degradation behavior of PANI in the nanocomposites has been investigated by thermogravimetric analysis. The weight loss suggests that the PANI chains in the nanocomposites are more thermally stable than pristine PANI. This improvement is attributed to the presence of nanolayers with high aspect ratio acting as barriers, thus shielding the diffusion of degraded PANI from the nanocomposites. The electrical conductivity of the nanocomposites was increased 30 times more than that of pure MMT at a certain concentration. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

On the structural and optical properties of gold–polyaniline nanocomposite synthesized via a novel route

Gold nanoparticle embedded polyaniline (PANI) was synthesized by in situ oxidative polymerization of monomer aniline. X‐ray diffraction and Fourier transform IR techniques were used to establish the structure of the gold–PANI composite. UV–visible absorption studies have shown that, along with the normal absorption peak of polyaniline, the composite has an absorption peak characterized by surface plasmon resonance. The presence of surface plasmon resonance is a signature of the nano size of the gold particles embedded in the PANI. Energy‐dispersive X‐ray spectroscopy (EDS) has revealed the elemental composition of the composite sample quantitatively. Raman spectroscopy studies have strengthened the presence of plasmon resonance. Single‐beam Z‐scan results confirm the third‐order optical nonlinearity associated with the nanocomposite. The present investigations show that gold nanoparticle embedded PANI composite can be of potential application in the fields of both linear and nonlinear optics. Copyright © 2012 Society of Chemical Industry     

Influence of medium on the nanostructure and properties of poly(4‐aminodiphenylamine)‐silver nanocomposites

Poly(4‐aminodiphenylamine)‐silver nanocomposites were synthesized by an easy one‐step aqueous chemical oxidative polymerization of 4‐aminodiphenylamine (4ADPA) using silver nitrate (AgNO₃) as the oxidant. Two different structure directing surfactants, p‐toluene sulfonic acid (p‐TSA) and cetyl trimethyl ammonium bromide/hydrochloric acid (CTAB/HCl), were independently used for the nanocomposite (NC) preparation. The NCs prepared in p‐TSA and CTAB/HCl medium were designated as P4ADPA/AgNC_(p?TSA) and P4ADPA/AgNC_(CTAB/HCl), respectively. We investigated the morphological variations in the NCs based on the medium. P4ADPA/AgNC_(p?TSA) and P4ADPA/AgNC_(CTAB/HCl) were characterized by field emission scanning electron microscopy, X‐ray diffraction analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis and UV‐visible spectroscopy. Copyright © 2011 Society of Chemical Industry     

Soft template method to synthesize polyaniline microtubes doped with methyl orange

A soft template method for fabrication of polyaniline (PANI) microtubes is presented in this paper. It was found that methyl orange in acidic solution can be effectively self-assembled into supramolecular aggregates like flake and dendrite and they were used as soft templates to prepare PANI microtubes in the present of aniline monomer and ammonium peroxydisulfate. The morphology and chemical structure of the PANI microtubules were characterized by means of transmission electron microscopy, scanning electron microscopy, Fourier transformed infrared spectra, UV–vis absorption spectra (UV–vis) and elemental analysis. The results showed prepared PANI microtubes were in conductive emeraldine state.     

Morphology controlled synthesis of polyaniline nanostructures using swollen liquid crystal templates

Preparation of zero‐dimensional and one‐dimensional nanostructures of polyaniline (PANI) were achieved by using swollen liquid crystals (SLCs) as ‘soft' templates. The monomer (aniline) was first entrapped in SLCs by replacing the oil phase (cyclohexane) with a mixture of aniline and cyclohexane. Zero‐dimensional nanostructures of PANI were obtained by thorough mixing of APS with the mesophases. One‐dimensional nanostructures were prepared by allowing slow diffusion of APS through the mesophase. PANI nanostructures were extracted from the mesophase and were characterized by UV‐visible spectroscopy, FTIR spectroscopy, powder X‐ray diffraction, atomic force microscopy, scanning electron microscopy (SEM), and conductivity measurements. A plausible mechanism for the formation of the nanostructures has been proposed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40800.     

Preparation and properties of 8‐hydroxyquinoline aluminum quinoline/polyaniline core–shell composite

Polyaniline (PANI) as an excellent conducting polymer material has been used to synthesize 8‐hydroxyquinoline aluminum quinoline/polyaniline (Alq₃/PANI) composites with core‐shell structure which is expected to form ultra‐conjugated system between core/shell and be used as organic electronic material. Alq₃ was coated by sodium dodecyl benzene sulfonate doped PANI via in situ polymerization of aniline on the surface of Alq₃. The morphology, structure crystallinity, and thermal stability of synthesized composite were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermal gravimetric analysis. Results indicated that the composite is core‐shell structure and exhibits good thermal stability. Conductivity of composite was investigated and showed that Alq₃ as core in composite which improved the conductivity of pristine PANI, indicating that electronic interactive effect was formed between core and shell. POLYM. COMPOS., 36:272–277, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of PbS/polyaniline core–shell nanocomposites based on octahedral PbS nanocrystals colloid

PbS/polyaniline core–shell nanocomposites were successfully synthesized via in situ chemical oxidation polymerization of aniline based on the octahedral PbS nanocrystals colloid. The morphology and structure of the products were characterized by transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectra, UV–vis spectra, and conductivity measurement. A possible formation mechanism of the PbS/polyaniline core–shell nanocomposites was also proposed. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Preparation of nanosize polyaniline by solid‐state polymerization and determination of crystal structure

BACKGROUND: Nanosize polyaniline has several advantages in both the fabrication of nanodevices and for preparing nanoscale electrical connections in highly conducting polymer composites. RESULTS: Nanosize polyaniline with a diameter of 30–60 nm was prepared using a solid‐state polymerization process (PANI‐S) by mixing an equimolar quantity of ammonium persulfate and anilinium chloride crystals with a mortar and pestle. Polyaniline was also synthesized using a conventional oxidative polymerization method (PANI‐C) in an aqueous medium for comparison. Conductivity and contact angle measurements, infrared spectroscopy, ultraviolet spectroscopy, transmission electron microscopy and thermogravimetric analysis were carried out. An in‐depth investigation of the crystal structure of these polymers was carried out through powder X‐ray diffraction analysis. CONCLUSION: PANI‐S exhibited lower conductivity due to the presence of less emeraldine base form, lower crystallinity, greater d‐spacing and greater inter‐chain separation than PANI‐C. The hydrophilicity and thermal stability of PANI‐S were higher than those of PANI‐C. The unit cell volume of PANI‐S was much higher, resulting in a larger crystallite size and a greater number of atoms in the unit cell than PANI‐C. Copyright © 2009 Society of Chemical Industry     

Fabrication and characterization of hybrid films based on polyaniline and graphitic carbon nitride nanosheet

Hybrid films of polyaniline/graphitic carbon nitride (PANI/g‐C₃N₄) deposited on titanium was fabricated. First, g‐C₃N₄ as a two‐dimensional graphite‐like structure was synthesized by the stepwise condensation reaction of melamine and cyanuric chloride in the presence of N,N‐dimethylmethanamide as a high boiling point nonnucleophilic base. Then composite films of PANI/g‐C₃N₄ were prepared by in situ electrochemical polymerization of an aniline solution containing g‐C₃N₄. Different concentrations of g‐C₃N₄ were utilized to improve the electrochemical performances of the hybrids. The resulting PANI/g‐C₃N₄ composite films were characterized by X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible diffuse reflection spectroscopy techniques. The electrochemical performance of the composites was evaluated by cyclic voltammetry (CV). Application of the prepared samples has been evaluated as supercapacitor material in 0.5 M H₂SO₄ solution using CV technique. The specific capacitances of PANI/g‐C₃N₄ composite films were higher than obtained for pure PANI films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44059.     

Preparation of agcl/polyaniline nanocomposite in polyvinylalcohol matrix and its electrocatalytic activity

AgCl/polyaniline (PANI) nanocomposite was successfully synthesized in polyvinyl alcohol (PVA) matrix via a two‐stage process. Firstly, positively‐charged Ag nanoparticles (NPs) were prepared in the presence of 4‐aminothiophenole (4‐ATP) as stabilizer. Then, polymerization of aniline was carried out in PVA matrix in the presence of Ag NPs, HCl, and ammonium persulfate as oxidant. HCl solution played an important role in the preparation of resulted nanocomposite. Removal or changing of acidic medium to camphorsulfonic acid influenced on the structure and morphology of obtained composites. The composites were characterized by scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, ultraviolet–visible spectra, and Fourier transform infrared spectroscopy. Moreover, AgCl/PANI/PVA nanocomposite was immobilized on the surface of a glassy carbon electrode and showed enhanced electrocatalytic activity for the oxidation of dopamine (DA) in a neutral solution. The peak currents of differential pulse voltammograms of DA increased linearly with concentration in the ranges of 80–250 μM DA and the detection limit for DA was 17.2 μM. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42366.     

Synthesis and characterization of a copolymer: Poly(aniline‐co‐fluoroaniline)

In the present article, we report the chemical synthesis and characterization of poly(aniline‐co‐fluoroaniline) [poly(An‐FAn)]. The copolymerization of aniline and 2‐fluoroaniline was carried out by chemical method in acidic medium. The characterization of poly(aniline‐co‐fluoroaniline) was done using FTIR, UV‐visible spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron micrography (SEM), and a four‐points‐probe conductivity method. X‐ray diffraction (XRD) and SEM characterization reveal crystalline nature of doped copolymer compared to undoped copolymer. The observed decrease in the conductivity of the copolymer relative to polyaniline is attributed to the incorporation of the fluoro moieties into the polyaniline chain. The chemically synthesized copolymer shows good solubility in common organic solvents, and is, therefore, technological useful. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1460–1466, 2001