Facile fabrication of polyaniline/polypyrrole copolymer nanofibers with a rough surface and their electrorheological activities

Hierarchical polyaniline/polypyrrole (PANI/PPy) copolymer nanofiber was prepared via a two‐step method and adopted as dispersing materials for electrorheological (ER) fluids. The first step was used to synthesize PANI nanofibers by a rapid mixing method. Subsequently, the PANI/PPy copolymer nanofibers with a rough surface were obtained using an in situ polymerization method continuously. The morphology of the resultant PANI/PPy copolymer nanofibers can be controlled by varying the amount of Py monomer in the secondary in situ polymerization method. The rough surface of PANI/PPy copolymer nanofibers were confirmed by scanning electron microscopy and transmission electron microscopy. The diameter of PANI/PPy nanofiber is within the range 100–200 nm. The obtained PANI/PPy copolymer particles all exhibit amorphous structure through X‐ray diffraction measurement. We also demonstrated that the hierarchical PANI/PPy copolymer nanofibers exhibited characteristic ER behaviors, which were investigated using a Haake rotational rheometer at various electric field strengths. The ER efficiency e for PANI‐1mLPPy and PANI‐2mLPPy ER fluids at shear rate 0.1 s⁻¹ is 36.6 and 28.5 under electric field strength E = 3 kV/mm, respectively. Low leaking current density is observed even at high electric field strength and wide plateau region appeared, which show a strong ER activity for the PANI/PPy composite nanofibers. The results also indicate that the PANI/PPy composite particles have distinctly enhanced ER effect compared with the pure PANI and PPy particles under electric stimuli. The significantly improved ER property of PANI/PPy‐based ER fluid is ascribed to the enhanced interfacial polarization. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46289.     

Electrospun polyaniline nanofibers web electrodes for supercapacitors

Polyaniline nanofibers (PANI‐NFs) web are fabricated by electrospinning and used as electrode materials for supercapacitors. Field‐emission scanning electron microscope micrographs reveal nanofibers web were made up of high aspect ratio (>50) nanofibers of length ～30 μm and average diameter ～200 nm. Their electrochemical performance in aqueous (1M H₂SO₄ and Na₂SO₄) and organic (1M LiClO₄ in propylene carbonate) electrolytes is compared with PANI powder prepared by in situ chemical oxidative polymerization of aniline. The electrochemical properties of PANI‐NFs web and PANI powder are studied using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. PANI‐NFs web show higher specific capacitance (～267 F g^?1) than chemically synthesized PANI powder (～208 F g^?1) in 1M H₂SO₄. Further, PANI‐NFs web demonstrated very stable and superior performance than its counterpart due to interconnected fibrous morphology facilitating the faster Faradic reaction toward electrolyte and delivered specific capacitance ～230 F g^?1 at 1000th cycle. Capacitance retention of PANI‐NFs web (86%) is higher than that observed for PANI powder (48%) indicating the feasibility of electro spun PANI‐NFs web as superior electrode materials for supercapacitors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of polyaniline nanofiber and copolymerization with acrylate through in situ emulsion polymerization

Polyaniline (PANI) was prepared, respectively, by direct mixed oxidation method in different acids. Scanning electron microscopy showed that high quality of PANI nanofibers can be obtained easily in hydrochloric acid, sulfuric acid, and acetic acid, especially in the sulfuric acid; infrared and ultraviolet spectra characterization showed all products were the doped PANI. Then, using complex emulsifiers, PANI was dispersed in acrylate emulsion by supersonic dispersion assisted with mechanical stirred to obtain mixed pre‐emulsion, the result showed different PANI performed different dispersing stability in the pre‐emulsion. More importantly, PANI–polyacrylate copolymer was prepared through multi‐steps in situ emulsion polymerization using water‐soluble azo (VA‐044) as initiator. Experiment showed that good dispersing stability of PANI in the pre‐emulsion was premise to obtain the final stable copolymer emulsion. Further, the micro‐morphology and thermal property of the copolymer were studied by transmission electron microscopy, differential scanning calorimetry, and thermogravimetric analyzer. The result proved that acrylate occurred in situ polymerization on surface of PANI nanofibers, the presence of PANI increased glass transition temperature (T_g) and thermal decomposed temperature of the copolymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polyaniline with high crystallinity degree: Synthesis,structure, and electrochemical properties

Polyaniline (PANI) with high crystallinity degree was facilely synthesized on the surface of stainless steel net by galvanostatic method. The effect of polymerization current density on the characteristics of morphology and structure had been investigated by field emission scanning electron microscopy (FE‐SEM), Fourier transforms infrared (FTIR), X‐ray photoelectron spectroscopy (XPS), and X‐ray diffraction (XRD). FE‐SEM observations disclosed that PANI was deposited as nanofibers and their diameters decreased with the polymerization current density. FTIR studies revealed that degree of oxidation increased in order PANI‐2 < PANI‐6 < PANI‐10. XPS measurements displayed that PANI polymerized at 6 mA cm^?2 (PANI‐6) exhibited much higher doping level of 77.8%, which favored the conductivity. XRD analysis discovered that the obtained PANI showed high crystallinity degree in which PANI‐6 possessed highest crystallinity degree (X_cr) up to 67%. Electrochemical performances of PANI as electrode materials were studied via cyclic voltammetry. The results presented that PANI‐6 possessed greater discharge capacity and better reversibility. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40827.     

Conducting polyaniline nanofiber networks prepared by the doping induction of camphor sulfonic acid

Branched nanofibers of conducting polyaniline (PANI) buried in the crystals of camphor sulfonic acid (CSA) were prepared from an m‐cresol solution of PANI and excessive CSA. After the excessive CSA was dissolved through ultrasonication in deionized water, networks of PANI nanofibers with spherical nodes, nanoparticles, leaf‐vein‐shaped nanofibers, and so forth were obtained according to the strength of the ultrasonic treatment. The X‐ray diffraction patterns of the CSA‐doped PANI showed high crystallinity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1537–1540, 2003     

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     

Preparation and characterization of polyaniline N‐grafted with poly(ethyl acrylate) synthesized via atom transfer radical polymerization

Polyaniline (PANI) N‐grafted with poly(ethyl acrylate) (PEA) was synthesized by the grafting of bromo‐terminated poly (ethyl acrylate) (PEA‐Br) onto the leucoemeraldine form of PANI. PEA‐Br was synthesized by the atom transfer radical polymerization of ethyl acrylate in the presence of methyl‐2‐bromopropionate and copper(I) chloride/bipyridine as the initiator and catalyst systems, respectively. The leucoemeraldine form of PANI was deprotonated by butyl lithium and then reacted with PEA‐Br to prepare PEA‐g‐PANI graft copolymers containing different amounts of PEA via an N‐grafting reaction. The graft copolymers were characterized by Fourier transform infrared spectroscopy, elemental analysis, and thermogravimetric analysis. Solubility testing showed that the solubility of PANI in chloroform was increased by the grafting of PEA onto PANI. The morphology of the PEA‐g‐PANI graft copolymer films was observed by scanning electron microscopy to be homogeneous. The electrical conductivity of the graft copolymers was measured by the four‐probe method. The results show that the conductivity of the PANI decreased significantly with increasing grafting density of PEA onto the PANI backbone up to 7 wt % and then remained almost constant with further increases in the grafting percentage of PEA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Electrospinning of solvent‐resistant nanofibers based on poly(acrylonitrile‐co‐glycidyl methacrylate)

This article reports on the preparation of novel solvent‐resistant nanofibers by electrospinning of poly(acrylonitrile‐co‐glycidyl methacrylate) (PANGMA) and subsequent chemical crosslinking. PANGMA nanofibers with diameters ranging from 200 to 600 nm were generated by electrospinning different solutions of PANGMA dissolved in N,N‐dimethylformamide. Different additives were added to reduce the fiber diameter and improve the morphology of the nanofibers. The as‐spun PANGMA nanofibers were crosslinked with 27 wt % aqueous ammonia solution at 50°C for 3 h to gain the solvent resistance. Swelling tests indicated that the crosslinked nanofibers swelled in several solvents but were not dissolved. The weight loss of all the crosslinked nanofibrous mats immersed in solvents for more than 72 h was very low. The characterization by electron microscopy revealed that the nanofibrous mats maintained their structure. This was also confirmed by the results of the pore size measurements. These novel nanofibers are considered to have a great potential as supports for the immobilization of homogeneous catalysts and enzymes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Fabrication of conducting polyaniline–multiwalled carbon nanotube nanocomposites and their use as templates for loading gold nanoparticles

A new and effective route to synthesize conducting polyaniline‐multiwalled carbon nanotube (PANI ‐f‐MWNT) nanocomposites (where ‘f’ denotes that the MWNTs have been functionalized) starting with amine‐protected 4‐aminophenol is reported. Aminophenol‐functionalized MWNTs were initially synthesized by functionalizing acyl chloride‐terminated nanotubes with N‐(tert‐butoxycarbonyl)‐4‐aminophenol followed by the in situ chemical oxidative grafting of aniline in the presence of ammonium persulfate as an oxidizing agent. Control of the morphology and thickness of the polymer–MWNT nanocomposites was achieved by varying the weight ratios of aniline monomers and MWNTs in the polymerization process. Fourier transform infrared spectroscopy was employed to characterize the initial changes in surface functionalities which also confirmed that PANI was covalently grafted to the MWNTs. Electron microscopy and UV‐visible absorption spectroscopy were employed to characterize the morphology and chemical structure of the resulting hybrids. The results obtained indicate that the structure of the MWNTs was not perturbed by the incorporation of PANI. The content of the polymer in the nanocomposites was determined thermogravimetrically, while the electrical conductivity was obtained using four‐probe measurements. The PANI ‐f‐MWNT nanocomposites were adopted as templates for further decoration with gold nanoparticles in solution, thus opening new possibilities for their prospective technological applications. Copyright © 2010 Society of Chemical Industry     

Poloxamer and gelatin gel guided polyaniline nanofibers: synthesis and characterization

A rapid polymerization technique was successfully employed to synthesize interconnected polyaniline (PANI) nanofibers using chemical oxidative polymerization inside a soft template. The thermoreversible hydrogels of Lutrol F 127 and gelatin were used as templates where the interstices present in the hydrogel were responsible for the formation of PANI nanofibers with a diameter in the range ca 70?75 nm and ca 50?55 nm respectively and several micrometers in length. The doped emeraldine salt of PANI was confirmed by Fourier transform infrared spectroscopy and ultraviolet–visible spectroscopy. The crystallinity of as‐synthesized PANI nanofibers for both cases was verified by an X‐ray diffraction study while thermogravimetric analysis was performed to compare the relative stability of the synthesized PANI nanofibers. The electrical conductivities of polymerized PANI are of the order of 10^?3 S cm^?1 and are compared with those of template fabricated PANI. The Lutrol F 127 gel guided PANI nanofibers showed a rectifying property while the gelatin gel guided PANI provided a simple ohmic nature. © 2013 Society of Chemical Industry     

Flame retardation and thermal stability of novel phosphoramide/expandable graphite in rigid polyurethane foam

A novel flame retardant named diethylene N,N',N''‐tri (diethoxy)phosphoramide (DTP) was synthesized using diethyl phosphate and diethylenetriamine via Atherton–Todd reaction. Then, series of flame‐retardant water‐blown rigid polyurethane foams (RPUFs) with expandable graphite (EG) and DTP were prepared through box‐foaming. The results of thermogravimetric analysis showed that DTP/EG changed thermal degradation process of RPUF and promoted enhancing char residues. The complex flame‐retardant system (EG/DTP) endowed RPUF higher limiting oxygen index (LOI) values (29.1%–30.2%) and lower heat release rate peak (PHRR) values according to LOI and microscale combustion calorimeter tests. More importantly, the synergistic flame‐retardant effect between EG and DTP in RPUF was proved by the analysis of synergistic effectivity values. Based on the analysis of cone calorimetric tests, EG/DTP revealed remarkable effects to inhibit the fire intensity and smoke release of RPUF with decreased PHRR and total smoke production due to good char‐forming action. To further investigate the char‐residues of the foams after combustion, scanning electron microscope and energy dispersive X‐ray spectroscopy analyses were conducted. The results suggested that EG/DTP flame‐retardant system promoted RPUF forming a compact, continuous and phosphorus‐rich char layer as a good fire barrier in combustion. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46434.     

Research on the preparation technology of polyaniline nanofiber based on high gravity chemical oxidative polymerization

Polyaniline (PANI) nanofibers with higher yield and homogeneous morphology were successfully prepared in larger scale by multi-step oxidation process with high gravity chemical oxidative polymerization (HGCOP) method in a rotating packed bed (RPB) under a higher initial aniline concentration of 0.5 M. The influence of oxidation times and ammonium peroxydisulfate (APS) dosages on the morphology, yield and conductive property of PANI were investigated, the products were characterized by SEM and UV–vis. Moreover, the anti-corrosion property and water dispersity of the as-prepared PANI nanofibers were also studied. The results showed that two-step oxidation process was an efficient way for mass production of PANI nanofibers by HGCOP, in which the optimum molar ratio of APS/aniline in the first and second oxidation stage was 0.5 and 0.25, respectively. PANI nanofibers with yield of 76.1%, diameters of 50–80 nm and average aspect ratio of 9.7 were obtained under the optimized condition. The PANI nanofibers were highly dispersible in water and exhibited an outstanding anti-corrosion effect, which could be applied to the environment-friendly processing and applications.     

Synthesis of higher soluble nanostructured polyaniline by vapor‐phase polymerization and determination of its crystal structure

Higher soluble nanostructured polyaniline was prepared by vapor‐phase polymerization after passing aniline vapor through an aqueous acidic solution of ammonium persulfate (PANI‐V). Polyaniline was also synthesized by the conventional oxidative polymerization method (PANI‐C) in an aqueous medium for the comparison of its properties with PANI‐V. PANI‐V exhibited lower conductivity but higher hydrophilicity and higher solubility (2–3 times) in different solvents, such as tetrahydrofuran, N‐methyl‐2‐pyrrolidone, dimethylsulfoxide, N,N‐dimethyl formamide, and m‐cresol at room temperature compared with that of PANI‐C. The thermal stability of PANI‐V was higher than that of PANI‐C. In‐depth investigations of the crystal structures of PANI‐C and PANI‐V were performed through powder X‐ray diffraction analysis. The PANI‐V showed a less ordered structure with a lower crystallinity and crystallite size and with a higher d‐spacing and interchain separation compared with PANI‐C. The unit cell volume of PANI‐V was significantly higher with a greater number of atoms in the unit cell than that of PANI‐C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Oxidative graft polymerization of aniline on the modified surface of polypropylene films

A novel method for preparing electrically conductive polypropylene‐graft‐polyacrylic acid/polyaniline (PP‐g‐PAA/PANI) composite films was developed. 1,4‐Phenylenediamine (PDA) was introduced on the surface of PP‐g‐PAA film, and then, chemical oxidative polymerization of aniline on PP‐g‐PAA/PDA film was carried out to prepare PP‐g‐PAA/PANI electrically conductive composite films. After each step of reaction, the PP film surface was characterized by attenuated total reflectance Fourier transform infrared spectroscopy. Static water contact angles of the PP, PP‐g‐PAA, and PP‐g‐PAA/PANI films were measured, and the results revealed that graft reactions took place as expected. The morphology of the PP‐g‐PAA film and the PP‐g‐PAA/PANI composite film were observed by atomic force microscopy. The conductivity and the thickness of the PP‐g‐PAA/PANI composite films with 1.5 wt % PANI were around 0.21 S/cm and 0.4 μm, respectively. The PANI on the PP‐g‐PAA/PANI film was reactivated and chain growing occurred to further improve the molecular weight of PANI. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2442–2450, 2007     

Effect of Ni2+ as a codopant on the structure,morphology, and conductivity of nanostructured polyaniline

One‐dimensional nanostructures of polyaniline (PANI) doped with (1S)‐(+)‐10‐camphorsulfonic acid (D‐CSA) alone and with NiCl₂ as a codopant were synthesized via in situ polymerization. PANI nanofibers with diameters of about 200 nm were formed when PANI was doped with D‐CSA only. When NiCl₂ was added as a codopant, the morphology of PANI obviously changed. The effects and related mechanisms were investigated by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, inductively coupled plasma–atomic emission spectroscopy, and X‐ray diffraction, and the results indicated that Ni²⁺ destroyed the micelles' structure by chemical conjunction with ? SO₃H groups in camphorsulfonic acid (CSA) molecules, which were the key component in forming the CSA–aniline micelles. The combination between Ni²⁺ and SO in CSA with a lower addition of Ni²⁺ led to a reduction of CSA doping to PANI, but a higher loading of Ni²⁺ brought about the direct doping of Ni²⁺ to PANI, which caused a higher degree of doping and oxidation. The conductivity of PANI increased almost linearly with increasing Ni²⁺. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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 microspheres with silicone oil cores and poly(N‐isopropylacrylamide) shells by physical coating

Surfactant‐free thermoresponsive microspheres with a silicone oil cores surrounded by poly(N‐isopropylacrylamide) shells have been successfully prepared by physical coating method for the first time. The influences of reaction temperature, N‐isopropylacrylamide (NIPAM) dosage, and stirring rate on the formation, morphology, particle size, and monodispersity of microspheres were experimentally studied. In the preparation of microspheres, when reaction temperature was above the lower critical solution temperature of poly(N‐isopropylacrylamide), products had higher yield of particles and narrower size distribution. With increasing NIPAM dosage, the particle diameter became larger and the shell layer thickened and the monodispersity became better. With increasing stirring rate, the particle diameter and the monodispersity decreased obviously. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5571–5576, 2006     

Thermal and morphological studies of chemically prepared emeraldine‐base‐form polyaniline powder

In this study, emeraldine base (EB)‐form polyaniline (PANI) powder was chemically prepared in 1M HNO₃ aqueous solution. The thermal characteristics and chemical structures of this powder were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and X‐ray diffraction (XRD). A polarizing optical microscope was also used to examine the crystalline morphology of this sample. The results indicated that the EB‐form PANI powder had a discernible moisture content. Moreover, in the first run of DSC thermal analysis, the exothermic peak at 170–340°C was due to the crosslinking reaction occurring among the EB‐form PANI molecular chains. FTIR and XRD examinations further confirmed the chemical crosslinking reaction during thermal treatment. TGA results illustrated that there were two major stages for weight loss of the EB‐form PANI powder sample. The first weight loss, at the lower temperature, resulted from the evaporation of moisture. The second weight loss, at the higher temperature, was due to the chemical structure degradation of the sample. The degradation temperature of the EB‐form PANI powder was around 420–450°C. The degradation temperature of emeraldine salt (ES)‐form PANI powder was lower (around 360–410°C) than that of the EB form (around 420–450°C). From the TGA results, I roughly estimated that 2.74 aniline repeat units, on average, were doped with 1 HNO₃ molecule in the ES‐form PANI. I found a single crystalline morphology of EB‐form PANI, mostly like a conifer leaf. More complex, multilayered dendritic structures were also found. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2142–2148, 2003     

Interfacial polymerization of morphologically modified polyaniline: from hollow microspheres to nanowires

BACKGROUND: Polyaniline (PANI) has attracted much attention in many fields due to its chemical and physical properties, and different nanostructures of PANI changing from one‐dimensional to three‐dimensional have been obtained. By changing the concentration of cetyltrimethylammonium bromide (CTAB), the morphology of hydrochloric acid‐doped polyaniline could be changed from one‐dimensional nanoneedles or nanowires with a network structure (50–100 nm in diameter) to three‐dimensional hollow microspheres (ca 400 nm in outer diameter) via combining interfacial polymerization and self‐assembly process. RESULTS These different nanostructures of PANI were proved using scanning electron and transmission electron microscopies. A plausible mechanism of the formation of the changeable nanostructures of PANI may be different from that of interfacial polymerization without surfactant or a traditional homogenous reaction system using CTAB as surfactant. CONCLUSION The results obtained from Fourier transform infrared spectrometry, X‐ray diffraction and the four‐probe method showed that the molecular structure of PANI does not change with increasing CTAB concentration, but crystallinity and conductivity of PANI increase with surfactant concentration. Copyright © 2007 Society of Chemical Industry     

Capacitive performance of polyaniline/manganese dioxide nanofiber microsphere

This work has obtained polyaniline/manganese dioxide (PANI/MnO₂) nanofibers microsphere by interfacial chemical synthesis with 4‐amino‐thiophenol (4‐ATP) as the structure‐directing agent on the Au substrate. The cyclic voltammograms, galvanostatic charge–discharge, and electrochemical impedance spectroscopy were used to determine their capacitive performance. Powder X‐ray diffraction, thermogravimetry and differential scanning calorimetry, Fourier transformed infrared spectroscopy, Brunauer–Emmett–Teller surface area measurements, and scanning electron microscope were performed for physical and chemical characterization. The effect of 4‐ATP and acids on the capacitive performance of PANI/MnO₂ nanofibers microsphere was elucidated. The as‐prepared PANI/MnO₂ was nanofiber about 30 nm diameters, and they further self‐assembled into sphere. Its specific capacitance is up to 765 F g^?1 at 1.0 mA cm^?2 in 1.0M Na₂SO₄ solution. And it shows a high stability with a capacitance fade of only 14.9% after 400 charge–discharge cycles. The symmetric capacitor of PANI/MnO₂ (PM10+)/PANI/MnO₂ (PM10?) is assembled in 1.0M Na₂SO₄ solution, and its capacitive performance is compared with that of PANI (+)/PANI (?) and MnO₂ (+)/MnO₂ (?). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40575.