Polypyrrole film architectures influence on platinum nanoparticles efficiency in ethanol electrooxidation

The electrodeposition of polypyrrole films from aqueous surfactant solution through a two‐dimensional polystyrene template onto indium‐tin oxide substrate has been investigated. The polymer grows in the interstitial spaces of the self‐assembled polystyrene spheres, which were subsequently removed by dissolution in toluene. The new obtained surface was characterized by scanning electron microscopy and atomic force microscopy. Platinum nanoparticles were deposited onto the nanostructured polypyrrole electrode and used as a catalyst for the oxidation of ethanol for direct ethanol fuel cells. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41375.     

Synthesis,characterization, and conductivity studies of polypyrrole/copper sulfide nanocomposites

Nanocomposites of polypyrrole (PPy) containing copper sulfide (CuS) were synthesized by an in situ chemical oxidative polymerization. The nanocomposites were characterized by FTIR, SEM, XRD, DSC, TGA, and conductivity studies. The FTIR spectra ascertained the chemical interlinking of polypyrole with metal sulfide nanoparticles. Morphological analysis showed that the nanoparticles were uniformly covering the entire substrate. The XRD pattern reveals that the nanoparticle incorporated polypyrrole showed a crystalline nature and the crystallinity of the polymer increases with increase in concentration of CuS nanoparticles. From DSC, an increase in glass transition temperature shows the increased orderness in the polymer composite than in the pure polypyrrole. Thermal analysis (TGA) of the composite showed a progressive increase in the thermal stability with increase in content of CuS. The frequency dependent electrical properties (a.c. conductivity) of the nanocomposites were higher than that of polypyrrole. The d.c. electrical conductivity increased with increase in amount of nanoparticles in the polymer matrix. The results obtained for these composites have greater scientific and technological interest. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Optical and structural properties of electrodeposited polyaniline/Q‐CdS composites

HCl doped polyaniline (PANI)/Q‐CdS composite thin films have been synthesized using the electrodeposition route on indium tin oxide (ITO) coated glass substrates. Three different sizes of CdS quantum dots were uniformly dispersed in PANI matrix. As deposited samples were characterized by X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). Optical properties of the composite structures were investigated by using optical absorption, photoluminescence, and Raman spectroscopy. PANI/Q‐CdS composite showed significant improvement in the thermal behavior as indicated by thermogravimetric analysis (TGA) thermograph. Our results also indicated that the doping state of the nanocomposites was dependent on the size of the CdS nanoparticles and improved with decreasing size. POLYM. COMPOS., 35:1864–1874, 2014. © 2014 Society of Plastics Engineers     

Fabrication and characterization of Ag-Decorated indium–tin-oxide nanoparticle based ethanol sensors using an enhanced electrophoretic method

In this paper different Indium Tin Oxide (ITO)-based ethanol vapor sensors (fabricated as thin films and nanoparticles) are presented, and their structural and sensing properties are investigated. An Electrophoretic Deposition (EPD)-Enhanced method is proposed for the fabrication of pure, and Ag-decorated indium tin oxide sensors. The proposed sensors are then compared to conventional indium tin oxide sensors fabricated by sputtering (thin film), and drop-casting method in terms of response, and working temperature. It is shown that the electrophoretic deposition method has decreased the final particle size of the indium tin oxide nanoparticles by limiting the agglomeration of nanoparticles, and increased the sparsity of the particles forming the sensing material. Results suggest that compared to the conventional sensors, the sensors fabricated by the proposed electrophoretic deposition method (i.e., the pure-indium tin oxide (EPD-TF), and the Ag-decorated indium tin oxide (Ag-EPD) sensors), has considerably better performance for the detection of the ethanol vapors, showing reduced working temperature (110 and 130 °C, respectively), higher response, and better selectivity over CO, methane, methanol, and acetone. Moreover, the response and recovery time of the proposed sensors were found to be lower than most of the previously reported indium tin oxide-based ethanol sensors, approving the positive effect of the electrophoretic method as a simple, controllable method for sensor fabrication.     

Preparation and properties of poly(ethylene terephthalate)/ATO nanocomposites

Antimony doped tin oxide (ATO) nanoparticles modified poly(ethylene terephthalate) (PET) composites used for manufacturing antistatic PET fiber were synthesized by in situ polymerization. The crystallization and multiple melting behavior of the nanocomposites were systemically investigated by means of Differential Scanning Calorimeter (DSC), Fourier Transform Infrared (FTIR), X‐ray Diffraction (XRD) techniques. The degree of crystallinity in nanocomposites increased with increasing ATO content. Smaller and more incomplete crystals are presented in the crystalline regions of the nanocomposites with increasing the content of ATO, which could be attributed to heterogeneous nucleation effects of ATO nanoparticles. Dynamic Mechanical Analysis (DMA) measurements showed that the storage moduli of the nanocomposites increased with increasing the content of ATO, due to formation of immobilized layer between polymer and filler. The interactions between ATO and PET molecules result in high tan δ for the PET/ATO nanocomposites. Percolation threshold of PET/ATO hybrid fibers prepared by the nanocomposites at room temperature was as low as 1.05 wt %, much lower than that of the composites filled with conventional conductive particles. Adding ATO nanoparticles obviously improves the conductivity of PET. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Hybrid polyaniline–TiO2 nanocomposite Langmuir–Blodgett thin films: Self‐assembly and their characterization

Polyaniline (PANi)–titanium dioxide (TiO₂) nanocomposite materials were prepared by chemical polymerization of aniline doped with TiO₂ nanoparticles. Surface pressure–area (π‐A) isotherms of these nanocomposites show phase transformations in the monolayer during compression process. Multiple isotherms indicate that the monolayer of the nanocomposite material can retain its configuration during compression‐expansion cycles. Langmuir–Blodgett thin films of PANi–TiO₂ nanocomposite were deposited on the quartz and indium tin oxide coated conducting glass substrates. Fourier transfer infrared spectroscopy and UV–visible spectroscopy study indicates the presence of TiO₂ in PANi, whereas X‐ray Diffraction study confirmed the anatase phase of TiO₂ and particle size (～nm) of PANi–TiO₂. The morphology of Langmuir–Blodgett films of these nanocomposites was also characterized by atomic force microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41386.     

Novel seed-assisted synthesis of indium tin oxide submicro-cubes and their resistivity

Indium tin oxide films, an important n-type semiconductor oxide, show great prospects in optoelectronic device applications. Consequently, as a key raw material of targets for sputtering films, it is important to prepare low-resistivity indium tin oxide powders. Herein, low-resistivity indium tin oxide submicro-cubes are synthesized by a seed-assisted coprecipitation method. The effects of seed content, In³⁺ concentration, aging time, reaction temperature and calcination temperature on resistivity were investigated by single factor and orthogonal experiments. To ensure reliability and reproducibility of data, each experiment was repeated three times and resistivity of each sample was measured three times to obtain average value. The results indicated that optimal sample was matched with cubic phase In₂O₃. The single-crystal indium tin oxide particles exhibited a regular cubic shape with a size of nearly 500 nm and low resistivity of 0.814 Ω·cm. Compared with particles prepared by the conventional coprecipitation method, indium tin oxide submicro-cubes showed good dispersion. The presence of seed particles provided nucleation sites with lower energy barriers and promoted formation of submicro-cubes. The face-to-face contact among particles and good dispersion contributed to electron transfer, resulting in lower resistivity. The seed-assisted synthesis provides a novel way to prepare low-resistivity indium tin oxide submicro-cubes.     

Visible light-driven CdSe nanotube array photocatalyst

Large-scale CdSe nanotube arrays on indium tin oxide (ITO) glass have been synthesized using ZnO nanorod template. The strong visible light absorption in CdSe, its excellent photoresponse, and the large surface area associated with the tubular morphology lead to good visible light-driven photocatalytic capability of these nanotube arrays. Compared to freestanding nanoparticles, such one-piece nanotube arrays on ITO make it very convenient for catalyst recycling after their usage     

An electrochromic device combining polypyrrole and WO3-I. Liquid electrolyte

In this work we assembled an electrochromic device using as active materials an organic conductive polymer and a transition metal oxide. We studied the materials used to assemble the device separately, and in complete devices. These materials were: polypyrrole doped with dodecylsulfate and tungsten oxide. The substrates used were glass slides coated with tin doped indium oxide, and the electrolyte was a propylene carbonate solution of lithium perchlorate. We adjusted the charge balance and the chromatic contrast of the devices by controlling the thickness of the polypyrrole films. To illustrate the results obtained, we describe two devices with different polypyrrole film thicknesses. The chromatic contrast in the visible and near-infrared wavelength range is 40% and the electrical and optical properties of the devices remain unchanged after 10⁴ double potential chronoamperometric steps.     

Facile template-free synthesis of pine needle-like Pd micro/nano-leaves and their associated electro-catalytic activities toward oxidation of formic acid

Pine needle-like Pd micro/nano-leaves have been synthesized by a facile, template-free electrochemical method. As-synthesized Pd micro/nano-leaves were directly electrodeposited on an indium tin oxide substrate in the presence of 1.0 mM H2PdCl4 + 0.33 M H3PO4. The formation processes of Pd micro/nano-leaves were revealed by scanning electron microscope, and further characterized by X-ray diffraction and electrochemical analysis. Compared to conventional Pd nanoparticles, as-prepared Pd micro/nano-leaves exhibit superior electrocatalytic activities for the formic acid oxidation.     

Effect of electrical properties on gas sensitivity of polypyrrole/cds nanocomposites

In the present work, polypyrrole (PPy) nanocomposites were synthesized using ferric chloride (FeCl₃) as an oxidant by in situ polymerization at room temperature. Cadmium sulfide (CdS) nanoparticles were synthesized by ultrasonication technique with size ranging between 60 and 110 nm. The PPy/CdS nanocomposites were prepared by taking 1–3 wt % loading of CdS to measure the electrical conductivity. The PPy nanocomposites were characterized by using FTIR, X‐ray diffraction, UV, and SEM. Furthermore, these PPy/CdS nanocomposites were investigated to study their effect of electrical properties on gas sensitivity of ammonia and LPG. The nanocomposites showed improvement in conductivity and sensing response toward 250 ppm NH₃ was found to be maximum (4.2) compared with 100 and 500 ppm NH₃ gas, whereas in the case of LPG, it showed sensitive response. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42379.     

Effect of stabilizer on synthesis of indium tin oxide nanoparticles

Indium tin oxide nanoparticles with shapes varying from sphere to cubic were synthesized by controlling the ratio of the concentrations of the protective polymer (PVP) to indium tin oxide precursor in their preparation by co-precipitation. Transmission electron microscopy was used to determine the size and shape. The XPS spectra of the particles revealed that the atomic ratios of In:Sn and (In + Sn):O are 10.0:1.0 and 1.0:1.5, respectively for both of the spheres and the cubes. X-ray diffraction study showed that these particles have the same crystalline structure. Thus, it is shown that the formation of the various shapes of the ITO particles could be achieved by using different ratios of protective polymer instead of varying the protective polymer or the sintering process.     

Facile precipitation of tin oxide nanoparticles on graphene sheet by liquid phase plasma method for enhanced electrochemical properties

A high-performance lithium ion battery (LIB) electrode was prepared by precipitating tin oxide nanoparticles on graphene powder by the liquid phase plasma (LPP) method. The particles generated by the LPP reaction are spherical SnO₂ nanoparticles with a size of 5-10 nm, as confirmed by a variety of analytical devices. The quantity of SnO₂ nanoparticles partially aggregated on the graphene sheet surface increases as the initial concentration of the tin precursor increases. The SnO₂/graphene nanocomposites (SGNC) electrodes prepared by the LPP method demonstrated improved cycling stability and reversible lithium storage capacity as compared to the bare graphene electrode. The precipitated tin oxide improves the lithium storage capacity, but excess tin oxide nanoparticles rather reduced the cycling stability.     

Preparation and Properties of Fe3O4/Polypyrrole/Poly(Pyrrole-Co-Acrylamide) Nanocomposites

Polypyrrole (PPy)/poly(pyrrole-co-acrylamide) (Poly(Py-co-AAm)/nanocomposite was prepared by a simple and inexpensive in-situ co-polymerization of pyrrole and acrylamide in the presence of Fe₃O₄ nanoparticles. The nanocomposites were characterized by FTIR, SEM, XRD, TGA, and conductivity measurements. The FTIR spectra ascertain the chemical interlinking of polypyrrole and copolymer with magnetite nanoparticles. The XRD revealed that crystallinity of the copolymer was increased with weight percentage of the magnetite nanoparticles. SEM analysis showed that the nanoparticles were well shaped and uniformly dispersed in the nanocomposites. Thermal stability and the electrical conductivity of the nanocomposite were higher than that of polypyrrole and the copolymer.     

Fabrication of polypyrrole/graphene oxide nanocomposites by liquid/liquid interfacial polymerization and evaluation of their optical,electrical and electrochemical properties

A novel route has been developed to synthesize polypyrrole (PPy)/graphene oxide (GO) nanocomposites via liquid/liquid interfacial polymerization where GO and initiator was dispersed in the aquous phase and the monomer was dissolved in the organic phase. The synthesized samples were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), ultraviolet–visible absorption (UV–vis), X-ray diffraction (XRD), electrochemical and electrical conductivity measurements. A good dispersion of the GO sheets within the PPy matrix was observed from the morphological analysis. The composites exhibited noticeable improvement in thermal stability and electrical conductivity in comparison to pure polypyrrole. The composites showed excellent electrochemical reversibility at the scan rate of 0.1 V/s and good cyclic stability even up to 100th cycle. Newly developed graphene oxide based polypyrrole composite could be applied in electrochemical energy storage device.     

Preparation and characterization of novel optically active poly(amide‐imide)/α‐Fe2O3 nanocomposites containing l‐alanine moieties

An optically active poly(amide‐imide) (PAI) was synthesized from the polymerization reaction of N,N′‐(Pyromellitoyl)‐bis‐l ‐alanine diacid chloride with 2,5‐diaminotoluene. The obtained inorganic metal oxide nanocomposites composed of PAI/nanostructured hematite (α‐Fe₂O₃) were synthesized through ultrasonic irradiation. The resulting nanocomposites were characterized by Fourier transform infrared spectroscopy, powder X‐ray diffraction, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The TEM results indicated that the nanoparticles were dispersed homogeneously in PAI matrix on nanoscale. TGA confirmed that the heat stability of the nanocomposites was improved in the presence of α‐Fe₂O₃ nanoparticles. POLYM. COMPOS., 37:1805–1811, 2016. © 2014 Society of Plastics Engineers     

聚吡咯/纳米氧化钇复合材料的结构与性能研究

用在位分散聚合法制得具有核壳结构的聚吡咯/纳米氧化钇复合材料,红外光谱和拉曼散射分析表明纳米氧化钇与聚吡咯之间存在化学作用,红外光谱有明显的蓝移现象,它们的反应发生在氮原子上。而随着Y2O3的加入,电导率呈下降的趋势。     

Simple One-Pot Preparation of In<Subscript>2</Subscript>O<Subscript>3</Subscript> Nano-particles Using a Supramolecular 3D Framework Polymer

An indium(III) three-dimensional coordination framework, [In₂(OH)₃(O₄C₈H₄)_1.5] _n (1), was synthesized by hydrothermal method and characterized by elemental analyses, X-ray powder diffraction (XRD) and IR spectroscopy. Indium(III) oxide nanoparticles was prepared by direct thermal decomposition of 1 at 450 °C in air. The indium(III) oxide nanoparticles were characterized by scanning electron microscopy, X-ray powder diffraction (XRD) and energy-dispersive X-ray analysis (EDAX). This study demonstrates the coordination polymer frameworks may be suitable precursors for a simple one-pot preparation of nanoscale metal oxide materials with different and interesting morphologies.     

Continuous Synthesis of Tin and Indium Oxide Nanoparticles in Sub- and Supercritical Water

Nanocrystalline tin and indium oxides (In₂O₃/SnO₂) were synthesized in sub- and supercritical water at 350°/380°C and 30 MPa in <73 s in a tubular flow reactor from an aqueous solution of {SnCl₄+InCl₃} (0.2 M ). The conversion rate for tin was 100%. Nanoparticles were analyzed by transmission electron microscopy (TEM), emitted X-rays, Raman, differential scanning calorimetry, and X-ray diffraction techniques. The bulk particles were composed of In, Sn, and O atoms, and made up of cubic In₂O₃ (10 nm) and tetragonal SnO₂ (5.5 nm) crystals. After calcination at 500°C for 2 h, little change occurred in the particle size and crystal phase. Traces of tin-doped indium oxide particles were also formed as confirmed by the TEM electron diffraction pattern. Using this one-step, high-temperature hydrothermal process, oxide nanoparticles can be continuously and conveniently produced in a well-controlled process.     

Characterization and physical properties investigation of conducting polypyrrole/TiO2 nanocomposites prepared through a one‐step “in situ” polymerization method

Nowadays, nanocomposites are a special class of materials having unique physical properties and wide application potential in diverse areas. The present research work describes an efficient method for synthesis of a series of polypyrrole/titanium dioxide (PPy/TiO₂) nanocomposites with different TiO₂ ratios. These nanocomposites were prepared by one‐step in situ deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl₃) as an oxidant in the presence of ultra fine grade powder of anatase TiO₂ nanoparticles cooled in an ice bath. The obtained nanocomposites were characterized by Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The obtained results showed that TiO₂ nanoparticles have been encapsulated by PPy with a strong effect on the morphology of PPy/TiO₂ nanocomposites. Also, the synthesized PPy/TiO₂ nanocomposites had higher thermal stability than that of pure PPy. The investigation of electrical conductivity of nanocomposites by four‐point probe instrument showed that the conductivity of nanocomposite at low TiO₂ content is much higher than of neat PPy, while with the increasing contents of TiO₂, the conductivity decreases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012