Prepare Polyaniline Nanofibers Research Articles

Unique Core-Shell Structured Polyaniline Nanofibers Toward Ultrahigh-Rate Flexible All-Solid-State Supercapacitor.

Promoting charge storage and fast charging capability simultaneously is a long-standing challenge for supercapacitors. A facile flowing seed polymerization is adopted to prepare polyaniline (PANI) nanofibers, in which phytic acid (PA) doped oligomers are first produced as the seeds for promoting the highly oriented growth of PANI nanofibers accompanying with the copolymerization of m-aminobenzene sulfonic acid (ASA) and aniline occurred on the surface of PANI nanofibers, as a result, unique core-shell structured PANI nanofibers are continuously fabricated. Benefitting from compact nanofiber structure, excellent dispersion, and self-doping effect, as-prepared PANI nanofibers exhibit a specific capacitance of 671.2 F g-1 at 2 A g-1 and ultrahigh rate capability of 93.1% from 2 to 100 A g-1. Then assembled all-solid-state supercapacitor can deliver the highest energy density of 28.3Wh kg-1 at a power density of 320.2W kg-1 with remarkable rate capability (81.2% from 1 to 20 A g-1), cycle stability (77.5% after 5000 cycles) as well as light weight and flexibility. It is highly desirable that the present green and scalable approach can be further applied to fabricate other unique core-shell structured PANI nanofibers with appealing potentials in energy storage devices.

Characterization of Prepared Polyaniline Nanofibers Based on a Hydrothermal Variation of Aniline Concentration

Characterization of Prepared Polyaniline Nanofibers Based on a Hydrothermal Variation of Aniline Concentration

Strong acid doping for the preparation of conductive polyaniline nanoflowers, nanotubes, and nanofibers

High-pressure CO2-supported aniline polymerization was thoroughly investigated with a focus on the effect of acid doping on the morphology of the prepared polyaniline (PANI). The polymerization was conducted using HCl at three different concentrations and H2SO4 as the doping agents. Self-assembled HCl-doped PANI nanoflowers (PANNFL) were synthesized for the first time by high-pressure CO2-supported polymerization in the presence of 2 M HCl. Furthermore, HCl-doped PANI nanotubes (HCl-PANNTs) and nanofibers (HCL-PANNFs), as well as sulfuric acid-doped PANI nanofibers (SUA-PANNFs), were successfully prepared by changing either the acidity of the reaction or the doping agent. With 0.1 M HCl doping, circular and rectangular cross-sectional HCl-PANNTs with a wall thickness of 40 nm were prepared. Upon increasing the acid concentration to 2 M HCl, the morphology of the PANI structures transformed from nanotubes to nanoflowers while retaining the same wall thickness. Further increasing the HCl concentration resulted in a mixture of nanosheet structures, and the amount of nanoflowers decreased. Additionally, 1.1 M H2SO4 doping produced nanofibers (SUA-PANNF) with an average fiber diameter of 45 nm. All the prepared PANIs had partially crystallized structure in the emeraldine salt form. Additionally, the crystallinities of the prepared HCl-PANI structures were higher than that of the SUA-PANI structure. It was clearly observed that the type of acid dopant and the acid concentration affected the polymerization yield (PY) and could control the electrical conductivity (EC). The highest EC, i.e., 3.7 S/cm, was exhibited by PANI prepared with 5 M HCl.

Experimental investigation on intensified convective heat transfer coefficient of water based PANI nanofluid in vertical helical coiled heat exchanger

In the present study, heat transfer enhancement with the use of water based PANI (polyaniline) nanofluid was investigated in vertical helically coiled tube heat exchanger. Initially, PANI nanofibers were prepared with the use of ultrasound assisted emulsion polymerization method. Then the prepared PANI nanofibers were dispersed in base fluid in varying concentration (0.1–0.5vol%) in order to get uniformly dispersed PANI nanofluid in the presence of sonication. The effect of PANI nanofibers concentration in nanofluid and Reynolds number on heat transfer coefficient have been investigated in helical coiled heat exchanger. It was found that the average heat transfer coefficient increases with an increase in the volume% of PANI nanofibers in nanofluid and Reynolds number. The heat transfer coefficient of base fluid i.e. distilled water was found to be 304W/m2°C (at xi/D=692.3) whereas it was found to be increased to 515.8W/m2°C (at xi/D=692.3) for 0.5vol% PANI concentration in nanofluid. The percentage enhancement in the heat transfer coefficient was found to be 10.52% at 0.1vol% of PANI nanofibers in nanofluid and was found to be increased to 69.62% for 0.5vol% of PANI nanofibers.

Studies On The Role Of Co-oxidant And Surfactant In Interfacial Polymerisation Of Polyaniline Nanofibers And Its Nonlinear Optical Limiting Applications

Herein, we have prepared Polyaniline (PANI) nanofibers by interfacial polymerization in the presence of co-oxidant and surfactant. The additives are found to have a profound impact on the polymers morphology and improved room temperature conductivity. It was found that PANI nanofibers prepared in the presence of aqueous sodium hypochlorite solution (NaOCl) and cetyl trimethyl ammonium bromide (CTAB) were of shorter diameter (30 nm) and high conductivity (6.59Scm -1 ) than those formed in the absence of those chemicals. The diameter of the fibers was intricately tuned by changing the ratio of NaOCl to aniline. The effect of co-oxidant and surfactant concentration in the nanofibers has been investigated with the help of SEM, IR, XRD, UV and conductivity studies. A comparative investigation with other surfactant sodium dodecyl sulphate (SDS) has been done and the variations in diameter were noted. We also studied the third-order optical nonlinearity and optical limiting properties of polyaniline nanofibers using a single-beam z-scan technique. The experiments were performed with a Nd-YAG laser at wavelength of 532 nm The mechanism behind nonlinear absorption could be predicted as two photon absorption. The results show that the polyaniline nanofibers have useful applications in futuristic nonlinear optics. Copyright © 2016 VBRI Press.

Simple and fast synthesis of polyaniline nanofibers/carbon paper composites as supercapacitor electrodes

A simple and fast electrochemical polymerization method is used to prepare polyaniline nanofibers supported on carbon paper. The composition and morphology of the obtained composites are characterized by infrared spectroscopy, X-ray diffraction and scanning electron microscopy. It is found that an aligned polyaniline nanofiber array is uniformly supported on carbon paper substrate. This unique array architecture provides good electrochemical supercapacitor performances for the obtained composites. A specific capacitance as high as of 531Fg−1 at a current density of 3mAcm−2 is achieved. The research data show that acceptable electrochemical properties can be attained by controlling the structure of supercapacitor electrode.

High performance of Pt-free dye-sensitized solar cells based on two-step electropolymerized polyaniline counter electrodes

Two-step cyclic voltammetry approach is employed to prepare polyaniline nanofibers, which supplies a quick and controllable method to obtain polyanilines with short-branched structure to increase the active surface area.

Synthesis and characterization of clay/polyaniline nanofiber hybrids

AbstractA modified interfacial polymerization was used to prepare polyaniline (PANI) nanohybrids. The influence of the synthetic route, amounts of bentonite, and the surfactant on the structure, morphology, and optical properties of the as‐synthesized nanocomposite were investigated. These materials were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction, ultraviolet–visible spectroscopy, thermogravimetric analysis, and rheometer. The results show that PANI could be intercalated into the interlayer of the bentonite. The interlayer space increased from 1.25 to 1.486 nm. Then, the hexadecyl trimethyl ammonium bromide was used to modify the surface of bentonite, which was helpful in hybridizing with PANI for its hydrophobic properties. Both the intercalated and coating structure were found in the bentonite/PANI nanohybrid. The TEM and SEM images verified that the surface of the bentonite plate was coated by PANI nanofibers. In addition, for the study of the electroresponsive behavior, the composite was dispersed in silicone oil, and its electrorheological characteristics were examined via both an optical microscope and a rheometer equipped with a high‐voltage power source. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Preparation of Polyaniline Nanofibers by High Gravity Chemical Oxidative Polymerization

To develop a suitable method for the mass production of polyaniline (PANI) nanofibers, the preparation of PANI nanofibers was carried out by high gravity chemical oxidative polymerization (HGCOP) in a rotating packed bed (RPB) for the first time. The influences of operating conditions, e.g., aniline concentration, high-gravity level, reaction temperature, and dopants, on the morphology of PANI nanofibers were investigated in detail. FTIR, UV−vis, XRD, molecular weight, and conductivity analyses were performed to characterize the products. Advantages of this new method are discussed. PANI nanofibers were successfully obtained in a wide range of aniline concentration (0.1−0.5 M) and reaction temperature (0−60 °C). The nanofibers kept small diameters of 30−50 nm and uniform morphology even when synthesized with a high initial aniline concentration of 0.5 M. This method provides a significant improvement to the rapid mixing route to prepare PANI nanofibers in large scale, moreover, it has potential applicatio...

Polyaniline nanofibers synthesized in compressed CO 2

Polyaniline (PANI) nanofibers were synthesized in compressed liquid carbon dioxide without any template or surfactant. The polymerization of aniline took place at the interface between CO 2 and aqueous solution in a high-pressure stirred reactor. The prepared PANI nanofibers were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), electrical conductivity (EC), Fourier-transform infrared (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) analyses. The yield of polymerization was high enough to reach 63.04% while maintaining small diameters of the PANI nanofibers. This result is very important for the preparation of the PANI nanofibers because no other previous investigations have achieved both high yield and small diameter of fibers at the same time. Through SEM and TEM analyses, we observed that the PANI nanofibers had diameter range of 30–70 nm and a length range of 0.3–1 μm, which caused them to disperse well in various solvents such as water, ethanol, 2-propanol, m-cresol and toluene. The electrical conductivity of the PANI nanofibers was 4.34 S/cm at 20 °C. The XRD diffraction pattern showed that the PANI nanofibers had crystalline one-dimensional structures, which gave high thermal stabilities as confirmed by TGA.

Morphology control of chemically prepared polyaniline nanostructures: Effects of mass transfer

Chemical oxidative polymerization of aniline was carried out in a high viscosity reaction system, created by dissolving a high molecular weight, water-soluble polymer – polyethylene oxide – into the polymerization reaction. It was found that mass transfer, which likely influences the nucleation and growth of the polymerization products, has significant effects on the morphology of chemically prepared polyaniline (PANI) nanostructures. One-dimensional PANI nanostructures obtained in the high viscosity system had obviously smaller sizes and aspect ratios, as species diffusion was suppressed, especially with further increased system viscosity. The growth of PANI nanostructures appeared to be heavily diffusion-limited when aniline polymerization was carried out using a moderate oxidant or at very low monomer concentrations (e.g. 0.005 M) in the high viscosity system, resulting in “coral reef”-like PANI clusters. Promoting mass transfer for the polymerization carried out under very low monomer concentration in the high viscosity system was beneficial for preparation of uniform PANI nanofibers.

Effects of ultrasonic irradiation on the morphology of chemically prepared polyaniline nanofibers

AbstractPolyaniline (PANI) nanofibers were chemically prepared through ultrasonic irradiated polymerization with varying ultrasonic power, frequency, and reaction temperature. It was found that PANI nanofibers with smoother surfaces and uniform diameters can be achieved by increasing the ultrasonic power or the reaction temperature in the studied ranges; a higher reaction temperature was also beneficial for producing PANI nanofibers with larger aspect ratios. With the ultrasonic power set to 250 W, although the polymer prepared at higher frequencies showed higher purity as well as smoother surfaces than those at lower frequencies, the one prepared at 50 kHz with uniform diameters of about 80 nm and lengths of about 700 nm performed best. With the ultrasonic power and frequency fixed and aniline polymerization carried out between 0 and 75°C, PANI nanofibers exhibiting larger aspect ratio and less agglomeration were obtained under a higher reaction temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Polyaniline Nanofibers: Inducing Action of Neodymium Oxide and Inhibiting Effect on Electrochemical Degradation and Modified Platinum Electrode Application to the Electrocatalytic Oxidation of Methanol

A simple chemical method was introduced to prepare polyaniline nanofibers in this article. According to the experimental results of scanning electron microscopy, Fourier transform infrared spectroscopy, inductively coupled plasma atomic emission spectra, critical micelle concentration (CMC) of toluene-p-sulfonic acid (p-TSA), electrokinetic potential (ζ-potential), and retarding contact angle (θ), the inducing action of neodymium oxide (Nd2O3) on the forming of polyaniline nanofibers was systematically studied. By means of cyclic voltammetry (CV) investigation, the electrochemical activity of the polyaniline in 0.1 mol L−1 H2SO4 aqueous solution and the electrocatalysis of platinum (Pt) electrode modified by the polyaniline nanofibers to methanol oxidation were studied. The results indicated that inducing action of Nd2O3 on the formation of polyaniline nanofibers was outstanding. Increasing the concentration of p-TSA contributed to the formation of the nanofibers. In the process of preparing platinum elec...

Electromagnetic interference shielding with polyaniline nanofibers composite coatings

AbstractHydrochloric acid doped polyaniline (PANI) nanofibers were synthesized by an interfacial polymerization with tetrachloride as the organic solvent and with a relatively higher aniline concentration. The doped PANI nanofibers were dispersed in cyclohexanone and the dispersion was mixed with solution of polyacrylate to prepare PANI nanofibers composite coatings. It was found that the yield of the doped PANI nanofibers can be as high as 23%, though a small amount of irregular shaped PANI particles and PANI nanofibers with relatively larger diameter were also obtained. The conductivity of the PANI nanofibers based composite coatings increased with the PANI nanofibers contents and a percolation threshold of 0.2 was demonstrated. The shielding effectiveness of the PANI nanofibers based coatings increased with PANI nanofibers loadings and shielding effectiveness as high as 63 dB can be achieved with PANI nanofibers loadings of 45%. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers

Chemical One Step Method to Prepare Polyaniline Nanofibers with Electromagnetic Function

AbstractA “Chemical one step method” (COSM) is proposed to prepare electromagnetic functional composite nanofibers of polyaniline (PANI/γ‐Fe2O3) having a diameter of ≈20 nm. In this approach FeCl3 is acts as the oxidant either for polymerization of aniline or for preparation of γ‐Fe2O3 magnets. Besides, it also provides protons produced by the hydrolysis process for doping PANI. It is found that the composite nanofibers have a high conductivity (10−1 ∼ 100 S · cm−1) and super‐paramagnetic properties (Ms = 0.46 ∼ 6.03 emu · g−1 and Hc = 0) at room temperature, where the conductivity is mainly affected by the molar ratio of FeCl3 to aniline monomer whereas the magnetic properties are dominated by the amount of FeCl2.magnified image