Preparation,FTIR spectroscopic characterization and isothermal stability of differently doped fibrous conducting polymers based on polyaniline and nylon-6,6

The fibrous conducting polymers based on polyaniline and nylon-6,6 are obtained by stirring with magnetic bar. The increase in the ratio of conducting polymer volume in case of such fibers make them attractive materials for potential applications. As it is difficult directly to form fibers of conducting polymers, stirring process is attempted to form fibers of conducting polyaniline and nylon-6,6. In the present paper, the fibrous polyaniline:nylon-6,6 (PANI:Ny-6,6) with different weight percentages (5–20%, w/w) are prepared by stirring process. The fibers obtained are characterized using Fourier-transform infrared spectra (FTIR) and scanning electron microscopy (SEM), the variation of electrical conductivity with different type doping agents 0.1 M (HCl, H₂SO₄ and HClO₄) and the stability in terms of DC electrical conductivity retention was studied in an oxidative environment by isothermal characteristics.     

Polymerization of pyrrole derivatives on polyacrylonitrile matrix,FTIR–ATR and dielectric spectroscopic characterization of composite thin films

Oxidative polymerization of acrylonitrile (AN) initiated by Ce(IV)–oxalic acid redox system in the aqueous medium was performed and polyacrylonitrile (PAN)/polypyrrole (PPy) composite thin films were prepared by polymerization of pyrrole on polyacrylonitrile matrix. Effect of concentration of pyrrole derivatives on the resulting polymeric film properties was investigated. The influence of the pyrrole derivative type and content on the dielectric permittivity, dielectric loss and electrical properties of the composite films were analyzed in the frequency range from 0.05 Hz to 10 MHz. For a selected concentration of 200 μl of composite films at 10⁷ Hz, the conductivity was found to be in the following order: PAN–PPy < PAN–PNMPy < PAN–PNPhPy. Dielectric constant increase of the composite films was more obvious when the quantity of n-phenyl pyrrole was increased. A linear relationship was observed between the absorbances (FTIR–ATR) and conductivities (dielectric spectroscopy).     

Morphology of conductive blend fibers of polyaniline and polyamide-11

Polyaniline (PANI), a member of the intrinsically conducting polymer (ICPs) family, was blended with polyamide-11 (poly-ω-aminoundecanoyle) in concentrated sulfuric acid. The above solution was used to spin conductive PANI/polyamide-11 fibers by wet-spinning technology. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed to study the two-phase morphology of the conductive PANI/polyamide-11 fibers. The micrographs of the cross-section, the axial section and the surface of the monofilament demonstrated that the two blend components were incompatible. The morphology of PANI in the fibers was of fibrillar form, which was valuable for producing conducting channels. The electrical conductivity of the fibers was from 10⁻⁶ to 10⁻¹ S/cm with the different PANI fraction and the percolation threshold was about 5 wt.%. By comparing the two blend systems of PANI/Polyamide-11 fibers and carbon black filled poly(ethylene terephthalate) (PET) fibers, it was shown that the morphology of the conductive component had an influence on electrical conductivity. The former had higher conductivity and lower percolation threshold than the latter.     

Preparation,degradation of polyaniline doped with organic phosphorus acids and corrosion essays of polyaniline–acrylic blends

Preparation and characterization of polyaniline (PANI) doped with anions containing phosphorus was investigated with the help of various technique. The chemical polymerization of aniline was carried out in acid media containing different anions of organic phosphorus acid with the use of ammonium peroxidisulfate as oxidant agent. The highest yield was observed in the case of styrilphosphonic acid. The conductivity increased in the following order: phenylphosphinic acid < 2chloroethylphosphonic acid < styrilphosphonic acid. The solubility tests carried out in DMF, DMSO and NMP showed that the presence of voluminous anions improves the solubility of doped PANI. The synthesized PANI was characterized by density, intrinsic viscosity, solubility, FTIR, UV–vis, NMR, conductivity and TGA measurements. The hardness, elasticity, resistance and protective behavior of acrylic films were determined. The acrylic dispersion based on PANI doped with anions containing phosphorus provides improved corrosion protection of carbon steel.     

Synthesis,characterization and spectroscopic studies of CdS/polyaniline core/shell nanocomposite

In this work, CdS/polyaniline (PANI) nanocomposite was synthesized by a novel method. Transmission electron microscope (TEM) images showed that the CdS/PANI nanocomposite had a core/shell structure. The crystal structure was studied using X-ray diffraction (XRD) and the obtained results showed that CdS had cubic structure. Fourier transform infrared (FTIR) spectroscopic measurements confirmed the formation of PANI at the surface of CdS nanoparticle. The prepared samples were further characterized using UV–visible (UV–vis) and fluorescence spectroscopy.     

Synthesis and characterization of organo-soluble conducting polyaniline doped with oleic acid

An emulsion polymerization process has been developed for the direct synthesis of the organo-soluble polyaniline (PANI) with oleic acid (OA) as the surfactant and dopant. The polyaniline doped with oleic acid (PANI/OA) powders, prepared by the proposed method, are highly soluble in many organic solvents such as dimethyl sulfoxide (DMSO), dimethyformamide (DMF) and N-methyl,2-pyrrolidinone (NMP). The PANI/OA powders were characterized by elemental analysis (EA), FTIR, UV–vis, TGA and SEM. The conductivities of the PANI/OA powders decreased with the increasing of the amounts of water in the emulsion polymerization.     

Preparation and electrical–magnetic properties of polyaniline doped with ionic ferrocenesulfonic acid

Conducting polyaniline with electrical conductivity of 2.34 × 10⁻¹ S cm⁻¹ was obtained using ferrocenesulfonic acid as dopant. After the ferrocenesulfonic acid was oxidized with FeCl₃, though the electrical conductivity of the doped polyaniline decreased by 1–2 orders of magnitude, the magnetic susceptibility (χ) increased with the increase of the oxidation degree of ferrocenesulfonic acid. EPR spectra showed not only a signal with a g value of around 2, but also a so-called half-field signal with a g value of about 4 even at room temperature. Coexistence of ferromagnetic intrachain interactions and antiferromagnetic interchain interactions in the materials has been suggested.     

Polypyrrole/conductive mica composites: Preparation,characterization, and application in supercapacitor

Polypyrrole/conductive mica (PPy/CM) composites were prepared by coating polypyrrole (PPy) onto the surfaces of the conductive mica (CM) via the in situ chemical oxidative polymerization method. The encapsulating morphologies were revealed with the scanning electron microscopy (SEM) technique. The PPy/CM composites were characterized with Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The composites possess high electrical conductivity at room temperature, the weak temperature dependence of the conductivity. Based on the cyclic voltammetry and the charge/discharge behavior of the PPy/CM composites, it was found that the composites performed typical electrochemical supercapacitor behavior.     

Preparation and characterization of polyaniline nanoparticles synthesized from DBSA micellar solution

Chemical oxidative polymerization of aniline was performed in a micellar solution of dodecylbenzene sulfonic acid (DBSA, anionic surfactant) to obtain conductive nanoparticles with enhanced thermal stability and processability. DBSA was used to play both the roles of surfactant and dopant. The polymerization kinetics and optimum polymerization conditions were determined by UV–VIS spectra. The optimum molar ratio of oxidant to aniline was 0.5 and DBSA content was the most important factor in the formation of polyaniline (PANI) salt. The polymerization rate was increased with increasing DBSA concentration. The reaction model was proposed on the basis of the roles of DBSA. The electrical conductivity varied with the molar ratio of DBSA to aniline and the highest conductivity of particles was 24 S/cm. The layered structure due to PANI backbone separated by long alkyl chains of DBSA was observed and it seems to facilitate the electrical conduction. The doping level of particle was fairly high and was dependent on the preparative conditions. The average size of the PANI particles determined by Guinier plot of small-angle X-ray scattering (SAXS) measurement was 20–30 nm, which was well coincidence with scanning electron microscopy (SEM) results     

Preparation and characterization of polyaniline nanostructures via a interfacial polymerization method

Polyaniline nanostructures have been formed successfully via a interfacial polymerization method using different organic solvents. These materials were characterized by using IR, UV–vis, TGA, SEM, TEM and AC-impedance spectroscopy. In impedance plot of polyaniline (interfacial polymerization) using different organic solvents, different equivalent circuits with distinct nature of arcs have been observed indicating different distribution ratio indicating diffusion-limited interfacial control of nucleation and growth of polyaniline nanostructures dependent on the different distribution ratio and different rates of transfer of aniline from organic phase to aqueous phase in different solvents.     

Preparation,characterization and sintering behavior of spherical iron oxide doped alumina particles

A continuous procedure for the preparation of homogeneous iron oxide doped alumina spherical particles is described. The method is based on the hydrolysis with ammonium hydroxide of liquid aerosols formed by spraying iron and aluminum nitrate aqueous solutions. The powder consisted of, according to X-ray diffraction and infrared spectroscopy, boehmite of low crystallinity. Heating of the as-prepared boehmite powders produced a series of transition aluminas that finally transform into the thermodynamically stable phase (α-Al₂O₃). It has been found that the temperature of such a transformation is lowered as iron oxide content in samples increases. Densification studies have shown that the presence of iron oxide has a beneficial effect on the sintering behavior of compacted powders. Thus, undoped samples did not achieve full density even after heating for 2 h at temperatures as high as 1500°C. In contrast, with 4 wt% iron oxide content full density microstructures, consisting of uniform equiaxed grains, were achieved after heating for 2 h at 1350°C.     

Preparation and characterization of fly ashes and polyaniline core/shell microspheres

To modify the surface of fly ashes (FAs), conductive polyaniline (PANI) layer were chemically grafted on the surface of the self-assembled monolayer (SAM) coated FA particles, resulting in SAM-FAs/PANI composites. The surface functionalization of FAs with amino groups was found to play an important role in the formation of the well-defined core/shell structure. The composites possess good conductivity, average specific capacitance and good magnetic properties at room temperature. Moreover, the conductivity stability and thermal stability of SAM-FAs/PANI composites were clearly improved. The resulting composites were characterized by using wide-angle X-ray diffraction analysis, Fourier transform IR spectroscopy, UV–vis spectroscopy, thermogravimetric analysis, and scanning electron microscopy.     

Preparation and enhanced stability of flexible supercapacitor prepared from Nafion/polyaniline nanofiber

Polyaniline nanofibers were used to produce a flexible supercapacitor electrode with a specific capacitance of 235 F g^?1. Cycle life and energy density were enhanced after encapsulating the polyaniline nanofiber electrode in Nafion. A specific capacitance of 195 F g^?1 was obtained over 10,000 charge–discharge cycles.A fully flexible, stand alone capacitor comprising two polyaniline nanofiber based electrodes and a PVDF separator was constructed. An initial specific capacitance of 125 F g^?1 (100 mV s^?1) was obtained. This decreased to 95 F g^?1 over 10,000 cycles.     

Preparation and characterization of ZnO/Cu/ZnO transparent conductive films

ZnO/Cu/ZnO transparent conductive thin films were prepared by RF sputtering deposition of ZnO target and DC sputtering deposition of Cu target on n-type (001) Si and glass substrates at room temperature. The morphology, structure, optical, and electrical properties of the multilayer films were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), UV/Vis spectrophotometer, and Hall effect measurement system. The influence of Cu layer thickness and the oxygen pressure in sputtering atmosphere on the film properties were studied. ZnO/Cu/ZnO transparent conductive film fabricated in pure Ar atmosphere with 10 nm Cu layer thickness has the best performance: resistivity of 2.3×10-4 Ω·cm, carrier concentration of 6.44×1016cm-2 , mobility of 4.51cm2·(V·s)-1 , and acceptable average transmittance of 80 % in the visible range. The transmittance and conductivity of the films fabricated with oxygen are lower than those of the films fabricated without oxygen, which indicates that oxygen atmosphere does not improve the optical and electrical properties of ZnO/Cu/ ZnO films.     

基于无颗粒银墨水制备柔性透明导电薄膜

以酒石酸银作为前驱体,1,2-丙二胺为络合剂,乙醇为溶剂制备无颗粒酒石酸银导电墨水。以丙烯酸乳液为原料制备模板,利用模板法和旋涂工艺法,在PET基材上制备透明导电银网格薄膜。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱仪(FTIR)等方法对制备的导电墨水和透明导电银网格薄膜进行表征。结果表明,该方法实现了银网格完全嵌入在裂纹模板凹槽中,通过调控模板的线宽大小及网孔数量可获得透过率为82%、方阻为28 Ω/sq的银网格透明导电薄膜。该导电薄膜的薄膜电阻经过100次弯曲后没有明显的变化,可以有效克服ITO薄膜柔性差的缺点。     

Synthesis, characterization and microwave absorption property of doped polyaniline nanocomposites containing TiO2 nanoparticles and carbon nanotubes

As nanomaterial possessing moderate conductivity, magnetic and dielectric property, novel hexanoic acid (HA)-doped polyaniline (PAni) nanocomposites containing TiO₂ nanoparticles (dielectric filler) and carbon nanotubes, CNTs (magnetic fillers such as single-walled carbon nanotube, SWNT and multi-walled carbon nanotube, MWNT) were prepared by template free method. The PAni were characterized by UV, FTIR, X-ray diffraction (XRD), thermogravimetric (TGA) and scanning electron microscopy (SEM) analyses. Conductivity, magnetization, dielectric and microwave absorption properties of PAni were also investigated. The resulted nanorods/tubes as shown in SEM images clearly show that polymerization is proceeded in micelle/water interface through elongation. During template free method, TiO₂ and CNT exist in the center of Ani/HA micelle. The SEM images show that some of the CNT enwrapped with PAni layer indicate CNT are just packed underneath the PAni and never attacked by PAni. PAni/HA/TiO₂/SWNT with 20% of SWNT exhibits the best microwave absorption property (99.2% absorption) with reflection loss of −21.7 dB at 6 GHz due to its moderate conductivity (1.27 S/cm), magnetization (M_s = 1.01 emu/g), highest tan δ and heterogeneity.     

Preparation and characterization of electromagnetic functionalized polyaniline/BaFe12O19 composites

Electromagnetic functionalized polyaniline/BaFe₁₂O₁₉ composites were synthesized by in situ polymerization of aniline in the presence of BaFe₁₂O₁₉ particles. The structure and morphologies of products were characterized by X-ray diffraction, infrared spectra, scanning electron microscopy and transmission electron microscopy. In the electromagnetic measurements, it was found that the ac conductivity of BaFe₁₂O₁₉ particles enhanced while the saturation magnetization and coercivity decreased after polyaniline coating.     

Electrochemical and physical characterization of lithium ionic salt doped polyaniline as a polymer electrode of lithium secondary battery

Polyaniline films doped with lithium ionic salts such as LiPF₆ and LiBF₄ were prepared by using the electrolyte solution mixture of ethylene carbonate and dimethyl carbonate. The doping level of the polyaniline films was confirmed by X-ray photoelectron spectroscopy and dc conductivity experiments. A doping mechanism of lithium ion through the interaction with a nitrogen at imine site is proposed. Electrochemical cells of Lipolyaniline-LiPF₆ or Lipolyaniline-LiBF₄ were assembled to investigate electrical capacity and its trends over the repeated charge/discharge cycles. The capacity of Lipolyaniline cell was increased and then saturated over 15 cycles. However, it did not reach the half of theoretical capacity of polyaniline material. The mechanism of electrochemical reaction during charge/discharge process of Lipolyaniline cell is presented.     

Composites of polyaniline and cellulose acetate: preparation,characterization, thermo-oxidative degradation and stability in terms of DC electrical conductivity retention

The composite films of polyaniline and cellulose acetate have been prepared by using two slightly different techniques. Thus-prepared polyaniline:celluloseacetate (PANI:CA) composite films were characterized by FTIR and SEM. The thermo-oxidative degradation was studied by thermogravimetric analysis (TGA) while the stability in terms of retention of DC electrical properties was studied in an oxidative environment by two slightly different techniques.