Viscoelastic characterization of semiconducting dodecylbenzenesulfonic acid doped polyaniline electrorheological suspensions

Dodecylbenzenesulfonic acid (DBSA)‐doped polyaniline particles were synthesized via emulsion polymerization, and electrorheological (ER) fluids were prepared by dispersing the synthesized polyaniline particles in silicone oil. The viscoelastic properties of DBSA‐doped polyaniline/silicone oil ER systems were examined using a vertical oscillation rheometer (VOR), which is designed for the rheological measurement of ER fluids, with a high voltage generator. Viscoelastic data obtained from the VOR were compared with those obtained from a commercial Physica rotational rheometer. The data from VOR were quite reliable in a broad range of both strain and frequency. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 108–114, 2001     

Electrorheological fluids based on nano-fibrous polyaniline

Using a modified oxidative polymerization, the nano-fibrous polyaniline with 200 nm diameter and several micrometer lengths was synthesized on a large scale and then was applied as a new electrorheological (ER) fluid. Compared to conventional granular polyaniline ER fluid, the nano-fibrous polyaniline ER fluid exhibited distinctly improved suspended stability. Under electric fields, the nano-fibrous PANI ER fluid also exhibited larger ER effect. Its shear stresses are about 1.2-1.5 times as high as those of the granular PANI ER fluid. At the same time, the shear stress of nano-fibrous PANI ER fluid could maintain a stable level and even an increase for the wide shear rate regions from 0.1 s⁻¹ to 1000 s⁻¹ under various electric fields. In addition, the dynamic experiment showed that the shear modulus of nano-fibrous polyaniline ER fluid under electric field was higher than that of the granular polyaniline fluid, which also confirmed the larger ER effect.     

Electrorheological properties of chemically modified chitosan suspension with various functional pendants

In this study, functional pendants of chitosan were focused on enhancing the shear stress of electrorheological (ER) fluids. Chitosan succinates and chitosan phthalate were synthesized for ER particles and ER fluids were prepared by dispersing the particles in silicone oil. After comparing the shear stress of all prepared ER fluids, obtained conclusions were that ER particle having two functional groups (one is +ve charge and another is ?ve charge) showed higher shear stress than that having only one functional group like the comparison between chitosan succinate(I) and chitosan succinate(II). However, though expect of the intermolecular overlapping between the π electrons clouds supporting the charge carrier generation and transport leading to a significant delocalization of electrons, chitosan phthalate shows lower shear stress than chitosan succinate(I) and chitosan succinate(II). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4937–4942, 2006     

Electrochemical synthesis and characterization of polyaniline thin film and polyaniline powder

The polyaniline thin film electrode and powder have been synthesized on graphite electrodes from 0.5 M hydrochloric acid solution under galvanostatic conditions. The water insoluble and acetone soluble polyaniline mass fractions of the powder, as well as the polymerization efficiency, based on the emeraldine salt have been determined. The morphology of the obtained emeraldine salt powder has been investigated by the optical microscopy.     

Preparation and characterization of soluble polyaniline

Polyaniline, which is soluble in common organic solvents, has been synthesized through the oxidative chemical polymerization of aniline in the presence of benzene diazonium chloride salt in an aqueous HCl acid medium. The blue‐black polyaniline thus prepared exists in a lower oxidation state than emeraldine. An X‐ray photoelectron spectroscopy study has shown that the intrinsic oxidation state of the polymer is 0.38. An elemental analysis has shown that the fractional doping level or degree of oxidation of the blue‐black polyaniline is 0.26. The product is believed to consist of a lower number of imine nitrogens in comparison with the polyemeraldine base. This fact is also corroborated by the lower electrical conductivity of the polymer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of malonic acid-doped polyaniline

The conductive form of polyaniline was synthesized by the anodic and chemical oxidation of aniline in malonic acid medium. The conductivity of polyaniline doped with malonic acid changed from 1.62×10–6 to 2.5×10–5Scm–1 depending on the way it was synthesized. The polymer growth rate was observed to be very slow in malonic acid compared with H2SO4. Thermogravimetric data revealed that the maximum thermal reaction rate of PANI doped with malonic acid was at 200°C and 520°C compared with 290°C and 530°C of the polymer doped with H2SO4.     

Preparation and characterization of polyaniline nanofiber colloids

Polyaniline (PANI) nanofibers were prepared via the reaction of aniline with ammonium persulfate carried out in ethylene glycol (EG) medium without water. These purified PANI nanofibers could be dispersed in water and other polar solvents, such as ethanol, EG, and N,N‐dimethylformamide, to form colloids. The morphology and structure of the PANI nanofibers were characterized and the effects of mechanical stirring on the morphology, structure, and electrical performance of PANI were investigated. The results indicated that the intermolecular H‐bonding interaction between molecules of PANI and alcohol is advantageous to the one‐dimensional growth of PANI, and a stirring reaction results in a lager size, a higher doping level, conductivity, degree of crystallinity, and oxidation than a nonstirring reaction. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.     

The characterization and application of p-type semiconducting mesoporous carbon nanofibers

The microstructures of mesoporous carbon nanofibers were characterized by scanning electron microscopy, transmission electron microscopy, nano-Raman, nitrogen adsorption-desorption and optical transmission. They possessed a high specific surface area 840 m² g⁻¹ and a 1.07 eV band gap. All mesoporous carbon nanofiber network can act as the channel material in p-type field-effect transistor devices with field-effect mobilities over 10 cm²/V s. Furthermore, mesoporous carbon nanofiber network exhibits better sensitivity and faster response to NO₂ gas than that of carbon nanotubes, which makes it a promising candidate as poisonous gas sensing nanodevices.     

Synthesis and characterization of polyaniline/NiO nanocomposite

Spherical nickel oxide (NiO) nanoparticles were prepared by using nickel chloride as precursor in the ethylene glycol as solvent and urea as precipitant. The X‐ray diffraction study showed that NiO has single‐phase cubic structure with average crystallite size of 35 nm. The prepared NiO nanoparticles were incorporated into polyaniline (PANI) matrix during in situ chemical oxidative polymerization of aniline with different molar ratios of aniline: NiO (12 : 1, 6 : 1, and 3 : 1) at 5°C using (NH₄)₂S₂O₈ as oxidant in aqueous solution of sodium dodecylbenzene sulfonic acid, as surfactant and dopant under N₂ atmosphere. The synthesized composites have been characterized by means of X‐ray diffraction (XRD), thermogravimetric analysis, Fourier transform infrared (FTIR), scanning electron microscopy, TEM, and vibrating sample magnetometer for its structural, thermal, morphological, and magnetic investigation. The XRD and FTIR studies show that the NiO particles are in the composite. The room temperature conductivities of the synthesized PANI, PANI/NiO (12 : 1), (6 : 1), and (3 : 1) composites were found to be 3.26 × 10^?4, 1.88 × 10^?4, 1.5 × 10^?4, and 4.61 × 10^?4 S/cm, respectively. The coercivity (H_c) and remnant magnetization (M_r) of NiO, PANI/NiO NCs (12 : 1), (6 : 1), and (3 : 1) at 5 K was found to be 8.22 × 10^?2, 6.31 × 10^?2, 6.42 × 10^?2, 6.27 × 10^?2 T, and 6.64 × 10^?3, 1.83 × 10^?4, 3.07 × 10^?4, and 3.98 × 10^?4 emu/g, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

聚苯胺/镍纳米复合材料的制备及其表征

以苯胺（An）、氯化镍（NiCl2×6H2O）为原料,原位聚合法合成聚苯胺/镍纳米复合微粒。采用X射线衍射仪、扫描电镜、傅里叶变换红外光谱仪、振动样品磁强计（VSM）及四探针测试仪技术表征了复合微粒的结构、形貌和电磁性能。结果表明：复合微粒在室温外加磁场下表现出铁磁性物质具有的磁滞现象,饱和磁化强度为9.44 emu/g,复合微粒在室温下的电导率为5×10-3 S/cm。     

Preparation and characterization of composites of polyaniline nanorods and multiwalled carbon nanotubes coated with polyaniline

Composites of polyaniline (PANI) nanorods and multiwalled carbon nanotubes (MWNTs) coated with PANI were prepared by in situ polymerization with perchloric acid as a dopant. Transmission electron microscopy images showed that the coexisting composites of PANI nanorods and MWNTs coated with PANI were formed at low MWNT contents. The interaction between MWNTs and PANI was proved by Fourier transform infrared and ultraviolet–visible spectra. The electrical conductivity of a dedoped PANI/MWNT composite with a 16.3 wt % concentration of MWNTs reached 3.0 × 10^?3 S/cm, which was 6 orders of magnitude higher than that of dedoped PANInanorods. The results also showed that coexisting composites of PANI nanorods and MWNTs coated with PANI had high electrochemical activity and good cyclic stability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Electrorheological suspensions

The electrorheological properties of polyaniline suspensions are typical of most electrorheological systems and are a function of many parameters such as suspension concentration, applied field strength and the relative permittivity of the particles. When only one parameter is varied, the suspensions' electrorheological effects increase with increasing concentration of dispersed phase, field strength and particle relative permittivity. The rheograms of the suspensions at different field strengths and concentrations have been studied. The dependence of the dynamic yield stress on particle concentration has also been determined.     

Synthesis and characterization of polyarylureas. I. Potentially semiconducting polymers

Polyarylureas were synthesized from the reaction between phosgene with aromatic diamines. Depending on the pH, the polyarylureas presented different colors when the solvent used was pyridine. The polyarylureas were characterized by IR spectroscopy, elemental analysis, and X‐ray photoelectron spectroscopy (XPS). To study the thermal stability of the polymers, a thermal degradation was performed between 35 and 700°C. The polyarylureas decomposed above 350°C. Without doping, polyarylureas are considered as semiconductors [σ = 10^?9 (Ωcm)^{? 1}]; after doping with I₂, their electrical conductivity increases by several orders of magnitude. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 822–830, 2001     

Preparation and characterization of fully oxidized form of polyaniline

Summary The oxidation state of polyaniline (PANI) can be varied from the fully reduced leucoemeraldine base (LEB) to the half oxidized emeraldine base (EB) and to the fully oxidized form pernigraniline base (PNB). In this work, the synthesis and properties of the highest oxidation state of polyaniline, pernigraniline, in the base as well as the corresponding salt form are discussed. Received: 10 May 2000/Revised version: 1 August 2000/Accepted: 1 August 2000     

Synthesis and characterization of polyaniline films using Fenton reagent

The chemical oxidation of aniline to form polyaniline (PANI) films and powder samples was made using Fenton reagent as an oxidizing agent in aqueous sulfuric acid medium. The PANI films were monitored by using the quartz crystal microbalance and the electronic absorption techniques. The optimum concentration was determined and the results were justified by measuring the UV–vis absorption spectra for the in situ PANI films. The conductivity for the PANI films and powder samples, prepared in different conditions, was measured. Also, the IR spectra, X‐ray and the thermogravimetric analysis for the PANI powder formed in the bulk were measured and compared with the polymer prepared using ammonium peroxydisulfate. A preliminary investigation to the dielectric properties of the polymer powder was measured and discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of polyaniline/carbon nanotube composites

The synthesis of polyaniline (PANI) containing different carbon nanotubes (CNTs) by in situ polymerization is reported in this study. The samples were characterized by X‐ray diffraction and scanning electron microscopy. Fourier transform infrared and ultraviolet–visible spectroscopy were used to determine the change in structure of the polymer/CNT composites. Thermogravimetric analysis showed that the composites had better thermal stability than the pure PANI. Photoluminescence spectra showed a blueshift in the PANI–single‐walled nanotube (SWNT) composite. Low‐temperature (77–300 K) electrical transport properties were measured in the absence and presence of a magnetic field up to 1 T. Direct‐current conductivity exhibited a nonohmic, three‐dimensional variable range hopping mechanism. The room‐temperature magnetoconductivity of all of the investigated samples except the PANI–SWNT composite were negative; however, it was positive for the PANI–SWNT composite, and its magnitude decreased with increasing temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and NMR characterization of a novel polyaniline derivative

Summary The synthesis and solution-state NMR investigation of the structure of a novel type of water-soluble polyaniline (PANI) derivative in leucoemeraldine and emeraldine oxidation states is presented. Copolymers of 3-aminobenzenesulfonic acid and 2-methoxyaniline (PMAOMA) with various monomer molar ratios were synthesized by chemical polymerization in a hydrochloric acid medium. Due to a large difference in the reactivities of 2-methoxyaniline (OMA) and 3-aminobenzenesulfonic acid (MA), the content of OMA in the copolymers was much higher (over 0.65 of the mole fraction) than in the reaction mixture. Structural characterization of the reaction products was performed using one- (¹H, ¹³C) and two-dimensional (GHSQC and GCOSY) NMR spectroscopy. The NMR data indicated an almost block structure of OMA sequences of variable length separated by shorter sequences of MA units. It was also shown that the incorporation of MA units in the copolymer chains favors the formation of a less oxidized material. Received: 9 May 2000/Revised version: 4 July 2000/Accepted: 4 July 2000     

Ultrasonic characterization of conductive epoxy resin/polyaniline composites

This study presents the ultrasonic characterization of conductive epoxy resin (ER)/polyaniline (PANI) composites. The prepared PANI is mixed with ER matrix at weight percentages of 5%, 10%, and 15% for preparing the ER/PANI composites. The effects of PANI amount on the mechanical properties of ER/PANI composites are investigated by ultrasonic pulse‐echo‐overlap method. Also, electrical conductivity, ultrasonic wave velocity and ultrasonic micro‐hardness values of ER/PANI composites are correlated. Experimental results show that there is an excellent correlation between ultrasonic micro‐hardness and ultrasonic shear wave velocity. Also, the results of ultrasonic velocities and elastic constants values illustrate that the appropriate combination ratio is 95 : 5 for ER and PANI in ER/PANI composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42748.     

The fabrication and characterization of inkjet-printed polyaniline nanoparticle films

This paper reports on the fabrication and characterization of electrodes modified with conducting polymer nanoparticle films, produced via inkjet printing. The polyaniline nanoparticle formulations were deposited via a desktop inkjet printer onto screen-printed carbon-paste electrodes (SPE), polyethylene terephthalate (PET) and gold-PET and their morphology studied at a range of length scales using profilometry, scanning electron microscopy and atomic force microscopy. The deposited films were found to form continuous polymer films depending upon film thickness, which was in turn dependent on the number of prints performed. The inkjet-printed films exhibited a smooth morphology on the SPEs at the micro-dimensional scale, as a result of the aggradation and coalescing of the nanoparticles upon deposition. The resulting modified electrodes were both conductive and electroactive, possessing good reversible polyaniline electrochemistry. Such a combination of materials and processing offers the potential of producing a range of low cost, solid state devices such as sensors, actuators and electrochromic devices.