Effects of dopant,coagulant, and reinforcing nanofiller on mechanical and electrical properties of wet-spun polyaniline nanocomposite fibers

This paper describes the application of Taguchi experimental design to study the simultaneous effects of the dopant, the coagulant, and multiwalled carbon nanotubes (MWCNTs) used as reinforcing filler on the properties (tensile strength and electrical conductivity) of polyaniline (PANI) nanocomposite fibers produced via a wet spinning process. The MWCNT content was found to be the most significant factor, accounting for 72.8 % of the total contribution of the three selected parameters to the tensile strength. The dopant contributed 17.6 %, while the coagulant had a negligible effect and was therefore pooled. MWCNT content provided the maximum contribution of 98 % to the electrical conductivity, whereas the dopant and the coagulant had negligible effects, with contributions of 0.021 % and 0.247 %, respectively. A scanning electron microscope (SEM) and a tapping-mode atomic force microscope (AFM) were employed to study the morphology of the fibers. The electrochemical and pseudocapacitive properties of the fibers were investigated using cyclic voltammetry (CV). The PANI-AMPSA-MWCNT presented a specific capacitance value of 12.8 F cm^?2. The thermal characteristics of the nanocomposite fibers were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Elemental analysis of the fibers showed a high degree of doping: about 47–55 %.     

Removal of toxic nitrate ions from drinking water using conducting polymer/MWCNTs nanocomposites

New application of conducting polymers as stable nanocomposites for nitrate ion exchange materials in water and wastewater treatment and for environmental protection is introduced in this work. The nanocomposites of multi-walled carbon nanotubes (MWCNTs) with different polymers such as: polyaniline (PANI), polypyrrole (PPY), poly(1,8-diaminonaphthalene) [P(1,8-DAN)] and poly(2-vinylpyridine) (P2VP) were synthesized with different dopants as effective and reusable nanocomposites for nitrate removal from drinking water. Nitrate anions at toxic concentrations were removed from water using ion exchange mechanism without any toxic byproducts. The obtained results demonstrate that effective ion exchange occurs between NO₃ ^? and Cl^?. There are some protonated heteroatoms in polymer chains that are bonded with anions of dopants and their counter ions in nanocomposites. These dopant anions on the =NH⁺– groups of polymers can be exchanged with NO₃ ^? in water. Adsorption of NO₃ ^? on polymer/MWCNTs nanocomposites showed dependency to some parameters. Different experimental parameters such as pH and temperature of the sample, polymers dopant, and the ratio of polymer to MWCNTs in nanocomposites affect the amount of nitrate removal. The highest removal efficiency was achieved at 1.20 g L^?1 of PANI/MWCNTs (3:1) nanocomposite, pH = 6.5 and ambient temperature. After five successive cycles of nitrate removal, this parameter was still up to 70 % compared to the first run (up to 80 %).     

Catalytic-assisted synthesis, characterization and low frequency AC conduction of nanostructured conducting polyaniline

Polymerizations of aniline at the reaction temperatures of 25 and 50 °C have been performed in the presence of iron catalyst. The prepared conducting polyaniline at different reaction periods was investigated for physicochemical and electrical properties, through X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR) and frequency-dependent electrical conductivity measurements, respectively. XRD studies established the improved nanostructured crystalline nature for the polymer prepared at 50 °C. Size of the particles ranging from 10 to 20 nm was calculated for the prepared polyaniline. SEM analysis shows the cauliflower-like morphology for optimized reaction temperature. The study further establishes the attainment of uniform distribution of polyaniline at the reaction temperature of 50 °C. The charge transitions between benzenoid (B-band) and quinonoid (Q-band) bands were witnessed by UV–Vis spectrum analysis. The band gap analysis revealed the narrow band gap direct transition semiconducting nature of the conducting polymer. Quinonoid and phenylene rings were identified through vibrational bands between 1570 and 827 cm^?1 via FTIR spectroscopy analysis. The AC conductivity of the sample synthesized at 50 °C showed 1.50 × 10^?1 S cm^?1. Enhancement in conductivity with increasing temperature represented the improved crystalline nature of the polyaniline prepared at 50 °C.     

Hybridization of graphene-reinforced two polymer nanocomposites

This article focuses on the hybridization of thermoplastic polymer matrices with conducting polymers and graphene derivatives. Polypropylene (PP), polymethylmethacrylate (PMMA) and polyoxymethylene (POM) were used as primary polymer matrices and polypyrrole (PPY) and polyaniline (PANI) as secondary conducting polymers. Highly conductive-reduced graphene oxide (rGO) and graphene (G) have been used as reinforcements. A Taguchi analysis has been performed for the blends to find the optimal combination of the blends with respect to electrical conductivity (σ) and mechanical properties. Both electrical and mechanical properties were improved by the hybridization process. The maximum electrical conductivity of 0.85 S.cm^?1 has been acquired with POM/PPY/G blend with 3 wt.% and 5 wt.% of PPY and graphene loading, respectively. The mechanical properties have been found to improve with all the blends but, PP/PPY/G blend with 3 wt.% and 6 wt.% of PPY and graphene loading displays overall better properties in comparison with other blends.     

Simultaneous Oxidation and Doping of Aniline to Polyaniline by Oxidative Template: Electrochemical Performance in Supercapacitor

Polyaniline salts containing sulfuric acid and cetyltrimethylammonium sulfate dopants were prepared by aqueous (PANI-Aq), emulsion (PANI-Em), and interfacial (PANI-In) polymerization pathways using cetyltrimethylammonium peroxodisulfate as an oxidative template. Formation of polyaniline was confirmed from infrared and X-ray diffraction spectral results. Value of conductivity (15 S cm^?1) of the polyaniline salt prepared by emulsion polymerization pathway was higher with that of the conventional polyaniline salt. PANI-Aq, PANI-Em, and PANI-In showed layered, flower petals, and nanorod and flower petals morphologies, respectively. These polyaniline salts were used as electrode in supercapacitor. Specific capacitance of PANI-Em, PANI-Aq, and PANI-In were 520, 484, and 474 F g^?1, which were higher than the conventional PANI-H₂SO₄ salt (390). Energy density was 26, 24.2, and 23.6 Wh kg^?1, respectively at a power density of 120 W kg^?1. After 3000 charge-discharge cycles, retention in the specific capacitance values of polyaniline salts was 86% (PANI-Em), 85.4% (PANI-Aq) and 76.1% (PANI-In).     

Acrylic acid‐doped polyaniline sensitive to ammonia vapors

Acrylic acid and HCl‐doped polyanilines were synthesized by chemical oxidative polymerization. The synthesized materials were used as sensors for ammonia. Comparison of the responses of the two polymers reveal that the acrylic acid‐doped polymer exhibits higher sensitivity and reversibility. Further, the resistance is observed to decrease on exposing the acrylic acid‐doped polyaniline to saturated ammonia vapors. A reversed trend is observed in the case of HCl‐doped polyaniline. The results are explained in terms of the differences in the chemical interactions of the two polymers with respect to ammonia vapors. The proposed mechanism is further supported by the X‐ray diffraction and FTIR analysis. The X‐ray diffractogram of acrylic acid‐doped polymer shows an enhancement in the crystallinity on exposure to ammonia vapors, while the HCl‐doped polymer exhibits a loss in crystallinity. The FTIR spectra shows a higher doping level in acrylic acid doped polymer as observed from the intense peak of the dopant ion at 1158 cm⁻¹, which is seen to be shifted to a lower wavenumber i.e. ∼1128 cm⁻¹ on exposing the polymer to ammonia vapors. On the other hand, in HCl‐doped polyaniline, the peak of the dopant ion ∼1120 cm⁻¹ is initially less intense, which is further suppressed on exposure to ammonia. Conductivity measurements show a large vapor‐induced increase in conductivity, in the case of ammonia‐exposed acrylic acid‐doped polyaniline, which results in the formation of a more crystalline‐conducting phase. Exactly the opposite results were obtained in the case of HCl‐doped polyaniline exposed to ammonia. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1994–1998, 2001     

Development of Polyaniline/Epoxy Composite as a Prospective Solder Replacement Material

In this paper we present a novel application of a conducting polymer, polyaniline, as a conductive filler for the development of isotropically conductive adhesives. We have developed isotropically conductive adhesives using protonic acid-doped polyaniline as the conducting filler in an anhydride-cured epoxy system. Fundamental material characterization like DSC, TGA and SEM of the samples was conducted to study their properties. Conductivity of these materials was measured by the four probe method while impact properties were studied by lap shear and drop tests. Samples were aged at 85°C/～100% RH for more than 500 h and the effects of aging were studied. Conductivity value of 10^?3 S/cm was obtained at 25% PANI filler concentration. These results demonstrate the potential of such systems to function as isotropically conductive adhesives.     

Synthesis and Characterization of NiS/MnS Core-Shell Embedded Conducting Polyaniline Composite for Photovoltaic Application

Conducting polyaniline (Pani) films embedded with Co²⁺ doped, PVA-capped NiS/MnS core-shell particles as photoluminescent boosters have been developed and reported. The absorption and photoluminescence characteristics of the core-shell Pani have increased significantly. Film of the core-shell-Pani composite is n-type semiconductor with a band gap of 2.34 eV. Periodic arrangement of the nanoclusters of the core-shell in the continuous conductive polymer matrix with high carrier density (3.99 × 10¹⁶) rates this material for photoelectrochemical applications. Solid-state photovoltaic cells with NiS/MnS-Pani as the electron conductor shows a I_sc of 0.14 mA/cm², V_oc of 382 mV and photo conversion efficiency of 1.25%.     

Synthesis of homo/3- and 4-armed hydrophilic glycopolymers: To promote aniline to polyaniline-glycopolymers for fluorescence,electro active material,and electrostatic discharge applications

Preparation of electrically conducting polymer film with homogeneity is very important work for electrical and electronic applications. In order to make homogenous conductive polyaniline film, we selected water soluble glycopolymer (GP), as dopant for polyaniline. Pendant carbohydrates water soluble glycopolymer architectures, such as, homo, 3 and 4 multi-armed polymers were prepared from methacryl-2,3,4,6-tetra-O-acetyl-D-glucopyranoside (MTAGP) monomer and EBrIB and 3- and 4-aremed initiators via ATRP polymerization followed by deacetylation process. This water soluble glycopolymer was used as dopant for polyaniline salt via the chemical oxidative emulsion polymerization of aniline using glycopolymer and surfactant by ammonium persulfate oxidant. Sulfate and dodecylhydrogen sulfate (DHS) groups are doped on polyaniline system via protonating H⁺, whereas, glycopolymer involves on polyaniline through hydrogen bonding (PANI-DHS-SA-GP). Coated film of PANI-DHS-SA-GP salt showed resistance in ESD range. PANI-DHS-SA-GP showed fluorescence and Hydrophilicity. Electrochemical performance of PANI-DHS-SA-GP as electrode material in supercapacitor cell was found from charge–discharge measurement. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48043.     

Thermal and dc Conductivity Behavior of Fly Ash Filled Polyaniline Composites

In this paper temperature dependence of dc conductivity (σ_dc) of emeraldine base form of polyaniline (PANI) and fly ash filled PANI are presented. Samples were prepared by in situ polymerization of aniline using ammonium persulphate as an oxidant and hydrochloric acid as dopant. Fly ash filled PANI composites were prepared by adding 3 gms of fly ash. Thermal characteristics of samples were measured using differential scanning calorimetry. The dc conductivity (σ_dc) of fly ash filled PANI was found to be on the order of 1.63 × 10^?11 s/cm at room temperature, which was lower than that of pure PANI. The activation energies calculated from σ_dc for PANI and the PANI 3 fly ash system were 1.35 and 1.16 eV, respectively. It was found that addition of fly ash to PANI drastically decreased the enthalpy from 2259.2 to 196.6 mJ. the endothermic peak due to the glass transition temperature shifted from 99.8 to 94.6°C. This was attributed to the change in the morphology of the composites on adding fly ash, as observed in the scanning electron micrographs.     

High-performance polymer/nanodiamond composites: synthesis and properties

Conjugated polymer/nanodiamond nanocomposites have been known as high-performance materials due to improved physical properties relative to conventional composites. In this attempt, novel conjugated polymer/nanodiamond nanocomposites were successfully prepared by in situ oxidative polymerization. Physical characteristics of the resultant nanocomposites were explored using Fourier transform infrared spectroscopy, field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscope, differential scanning calorimeter, thermogravimetric analysis and X-ray diffraction spectroscopy. Structural analysis revealed the oxidative polymerization of various matrices [polyaniline (PANi), polypyrrole (PPy), polythiophene (PTh) and polyazopyridine (PAP)] over the surface of functionalized (F-NDs) and non-functionalized nanodiamonds (NF-NDs) thus ensuing NF-NDs/PAP/PANi/PPy, F-NDs/PAP/PANi/PPy, NF-NDs/PANi/PPy/PTh and F-NDs/PANi/PPy/PTh nanocomposites. FESEM images depicted the fibrillar morphology of resulting nanocomposites with granular arrangement of nanofiller in matrix. Thermal analysis results showed that the functionalized F-NDs/PAP/PANi/PPy hybrid had higher value of 10 % weight loss around 489 °C relative to F-NDs/PANi/PPy/PTh with T₁₀ at 471 °C. The glass transition temperature was found to be 99 and 105 °C for NF-NDs/PANi/PPy/PTh and F-NDs/PANi/PPy/PTh, respectively. On the other hand, NF-NDS/PAP/PANi/PPy and F-NDs/PAP/PANi/PPy showed higher T _g’_s of 109 and 118 °C. The conductivity of NF-NDs/PAP/PANi/PPy was 3.8 Scm^?1 and improved with the functionalized filler loading in F-NDs/PAP/PANi/PPy up to 5.4 Scm^?1, while NF-NDs/PANi/PPy/PTh and F-NDs/PANi/PPy/PTh had relatively lower values around 2.9 and 3.7 Scm^?1, respectively. New conducting nanocomposites may act as useful contenders in significant industrial applications such as polymer Li-ion battery.     

Sulfonate based ionic liquid incorporated polymer electrolytes for Magnesium secondary battery

The polymer electrolytes comprising of PVdF-HFP/PVAc/Mg(ClO₄)₂ as salt based polymer blend electrolytes derived from the addition of varying amounts of 1-ethyl – 3-methylimidazolium trifluoromethane sulfonate [EMITF], as dopant were synthesized in the form of films by solution-casting method. The XRD and FTIR patterns confirm the formation of an amorphous phase and also that complex formation between the polymers, salt and ionic liquid. The SEM images show that the polymer electrolyte exhibit a enormous pores, remarkably, the maximum ionic conductivity is obtained in the case of the typical polymer system I₃ is found to be 9.122 × 10^?4 Scm^?1at 303 K.     

Inverted emulsion cast electrically conducting polyaniline–polystyrene blends

An inverted emulsion method for the synthesis of electrically conductive polyaniline–polystyrene blends of different compositions (10, 30, 50, 70, and 85%, wt/wt) is described. Polymerization of aniline is carried out in chloroform in the dispersed phase by using benzoyl peroxide as a novel oxidant and sulfosalicylic acid as the dopant. The blends synthesized with benzoyl peroxide as the oxidant are of high purity and the excess benzoyl peroxide is readily removed with acetone, which is used to break the emulsion and precipitate the polymer. The absorption spectra, FTIR, FT Raman, and electron paramagnetic resonance spectroscopy confirm the presence of polyaniline in the salt form and polystyrene in the blend. The thermal stability of polyaniline salt decreases with an increase in polystyrene content in the blend. The SEM studies show that the particles of polyaniline–sulfosalicylic acid are dispersed on the polystyrene surface. The blends of polyaniline–polystyrene prepared by the present method were found to display conductivities as high as 0.5–0.1 S cm^?1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1163–1171, 2002     

Effect of composition on the conductivity and morphology of ligno sulfonic acid sodium salt doped polyaniline

A systematic approach is developed to study the ligno sulfonic acid sodium salt (LSA) protonation or doping process with polyaniline emeraldine base (Pani‐EB) in organic solvents like dimethyl sulfoxide, and the influence of LSA‐doping on the properties of polyaniline was investigated in detail. The composition of Pani‐EB and LSA was varied in the weight ratio of 1:1 to 1:50 to investigate the effect of the dopant concentration on the conductivity and morphology. The doping process was confirmed by UV–vis and FTIR spectroscopes. The composition analysis indicates that only 50% of the LSA is used for the doping process irrespective of the weight ratio of LSA/Pani‐EB in the feed. The four probe conductivity measurement suggests that the conductivity of the doped samples are increasing with the increase in the ratio of Pani‐EB/dopant composition, and the high conductivity of the doped material was obtained in the range of 1.0 × 10^?2 S/cm. Scanning electron microscopy reveals that LSA induces a selective aggregation in the polyaniline chains to produce needlelike or rod‐shape morphology of sizes having ～0.2 μm diameter and 1 μm length. At very higher amount of LSA, the microrods are completely collapsed and form uniform continuous morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2650–2655, 2006     

Preparation and self‐assembly of polyaniline nanorods and their application as electroactive actuators

To improve the performance of ion‐exchange polymer–metal composite (IPMC) actuators, an electrical pathway material for enhancing the surface adhesion between the membrane and the metal electrodes of the IPMC was studied. As an efficient electrical pathway material, polyaniline nanorods (PANI‐NRs) doped with p‐toluene sulfonic acid (TSA) were synthesized with a template‐free method. The factors affecting polyaniline morphology were studied with various dopant concentrations and oxidant feeding rates. Highly conductive PANI‐NRs were formed when they were synthesized with ammonium persulfate at a 5.0 mL/min oxidant feeding rate and doped with 0.125M TSA. The conductivity of the PANI‐NRs was 1.15 × 10^?1 S/cm, and their diameters and lengths were 120–180 nm and 0.6–2 μm, respectively. To apply the membrane as an actuator, perfluorosulfonated ionomer (Nafion)/PANI‐NR blends were prepared by solution blending and casting. The actuating ability of the three‐layered membrane consisting of Nafion/PANI‐NR blends was then examined and compared with that of Nafion only. The actuating ability of the IPMC was improved when Nafion/PANI‐NRs were used as electrical pathways. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,Characterization and Conducting Properties of Nanocomposites of Intercalated 2-Aminophenol with Aniline in Sodium-Montmorillonite

A simple method was used to synthesize poly(2-aminophenol), poly(2-aminophenol-co-Aniline) and polyaniline nanocomposites with sodium-montmorillonite (Na-M) using in situ intercalative oxidative polymerization. Morphology and thermal properties of the synthesized nanocomposites were examined by transmission electron microscopy (TEM) and thermogravimetric analysis. The thermal analysis shows an improved thermal stability of the nanocomposites in comparison with the pure poly(2-aminophenol). The intercalation of polymers into the clay layers was confirmed by X-ray diffraction studies, TEM images and FTIR spectroscopy. In addition, the room temperature conductivity values of these nanocomposites varied between 8.21 × 10^?5 and 6.76 × 10^?4 S cm^?1. The electrochemical behavior of the polymers extracted from the nanocomposites, has been analyzed by cyclic voltammetry. Good electrochemical response has been observed for polymer films; the observed redox processes indicate that the polymerization into Na-M produces electroactive polymers.     

Studies on SLS doped polyaniline and its blend with PC

Electrically conductive polyaniline (PANI) and its blend with polycarbonate (PC) was prepared by one-step emulsion polymerization technique in which sodium lauryl sulfate (SLS) acts as surfactant and as a protonating agent for the resulting polymer. The prepared PANI and its blends were characterized by density, percentage of water absorption, and electrical conductivity. PANI–PC blend exhibits a conductivity value of 4.70 × 10⁻² S/cm (PANI–PC1) and 5.68 × 10⁻⁵ S/cm (PANI–PC3) with a change in dopant from p-toluene sulfonic acid (TSA) to SLS, respectively. By using a more general method, which takes into account the presence of disorder of the second kind in polymers proposed by Hosemann, crystal size (〈N〉) and lattice strain (g in %) values were estimated. The variation of conductivity in doped PANI and PANI–PC blend has been explained on the basis of these microcrystalline parameters. TGA thermograms of PANI and PANI-PC blend show three-step degradation behavior. Thermal stability of PANI was improved after blending with PC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 383–388, 2001     

Electroluminescent Performances of Iridium Complexes with Dibenzo-18-crown-6

Three novel iridium complexes with dibenzo-18-crown-6 substituted 2-penylpyridine (ppy) ligand have been synthesized and characterized. In order to investigate the electroluminescent properties of the resulting iridium complexes, polymer light-emitting diodes (PLEDs) with device structure of ITO/PEDOT:PSS/Emissive Layer/LiF/Al are fabricated using soluble poly(N-vinylcarbazole) (PVK) as the host and the resultant iridium complexes as dopant. Consequently, the PLEDs with G1 as dopant exhibited the highest luminous efficiencies of 13.3 cd A^?1 and the maximal brightness of 13523 cd m^?2 at the doping concentration of 8 wt%. Moreover, the iridium complexes G1, G2 and G3 exhibited nearly identical Commission Internationale de L’Eclairage (CIE) coordinates of (0.34?±?0.1, 0.62?±?0.1), which are very close to the CIE coordinates of (0.33, 0.61) for Ir(ppy)₃. This indicates that the CIE coordinates of the iridium complexes would not be influenced as the dibenzo-18-crown-6 groups pended on the meta-position of benzene ring of ppy.     

pH electrodes constructed from polyaniline/zeolite and polypyrrole/zeolite conductive blends

A new type of solid state electrodes sensitive to pH changes is described, in which the chemical‐sensitive layer consists of Pt microparticles deposited on a conducting polymer (polyaniline, polypyrrole) blend containing 22.7% w/w zeolite. These sensors are stable in aqueous electrolyte solutions of low pH value at temperatures up to 45°C with response time in seconds. At 25°C, sensor sensitivity was ?310 ± 40 mV/pH and ?1300 ± 100 mV/pH for polyaniline and polypyrrole blends, respectively. Interferences appear to be acceptably small. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1853–1856, 2006     

Preparation and capacitance performance of polyaniline/titanium nitride nanotube hybrid

A polyaniline/titanium nitride (PANI/TiN) nanotube hybrid was prepared and used for an electrochemical supercapacitor application. Firstly, the well-aligned TiN nanotube array was prepared by anodization of titanium foil and subsequent nitridation through ammonia annealing. Then, PANI was deposited into TiN nanotube through the electrochemical polymerization process. The obtained PANI/TiN nanotube hybrid had an ordered porous structure. A high specific capacitance of 1,066 F g^?1 was obtained at the charge–discharge current density of 1 A g^?1 when only the mass of PANI was considered. The specific capacitance can even achieve 864 F g^?1 at 10 A g^?1 and still keep 93 % of the initial capacity after 200 cycles. An aqueous supercapacitor, consisting of two symmetric PANI/TiN nanotube hybrid electrodes and 1.0 M H₂SO₄ electrolyte solution, showed the specific capacitance of 194.8 F g^?1, energy density of 9.74 Wh kg^?1, and power density of 0.3 kW kg^?1.