Enhanced electrical conductivity of Ag-mercaptosuccinic acid-redoped polyaniline nanoparticles during thermal cycling above 200 °C

Ag-doped polyaniline (PANI) nanoparticles are prepared via doping-dedoping-redoping with the thiol group in mercaptosuccinic acid (MSA) providing the linkage between PANI molecules and Ag atoms. Ag-MSA-doped PANI maintains the electrical conductivity well above the room-temperature value of 3.0 S/cm up to 220 °C, reaching its maximum (9.0 S/cm) at 180 °C. In addition, Ag-MSA-doped PANI nanoparticles show remarkable stability against repeated thermal aging at 120 °C. The room-temperature conductivity, in fact, increases by a factor of ∼3 after 3 cycles of thermal aging. The enhanced stability against repeated thermal aging is attributed to the formation of uniformly distributed Ag nanoparticles within the PANI particles upon heating.     

Synthesis,Electrical Conductivity,Spectral and Thermal Stability Studies on Poly(aniline-co-o-nitroaniline)

o-Nitroaniline units were incorporated in the polyaniline backbone through copolymerization with aniline. The copolymers were synthesized for 1:3 and 1:1 molar ratios of aniline and o-nitroaniline in acidic medium using potassium persulphate as oxidant and their properties were compared with that of polyaniline. The polymers showed less electrical conductivity than polyaniline. Unlike polyaniline, the presence of nitro group caused higher frequency dependence of electrical conductivity. Electronic spectra showed a blue shift in both the band of the copolymers due to the decrease in the extent of conjugation leading to lower conductivity, which could also be explained in terms of a decrease of delocalization of electron as evinced from electron para magnetic resonance (EPR) data. Thermo gravimetric analysis (TGA) revealed that copolymer derived from 1:1 molar ratio showed comparable thermal stability with polyaniline and the one derived from 1:3 molar ratios is thermally less stable than polyaniline. Activation energies for thermal degradation were estimated using Broido equation. The temperature dependence of electrical conductivity suggested charge transport is mainly through variable range hopping.     

Study of a PCM based energy storage system containing Ag nanoparticles

In this paper, organic phase change materials (PCM)/Ag nanoparticles composite materials were prepared and characterized for the first time. The effect of Ag nanoparticles on the thermal conductivity of PCM was investigated. 1-tetradecanol (TD) was selected as a PCM. A series of nano-Ag-TD composite materials in aqueous solution were in-situ synthesized and characterized by means of thermal conductivity evaluation method, TG-DSC, IR, XRD and TEM. The results showed that the thermal conductivity of the composite material was enhanced as the loading of Ag nanoparticles increased. The composite materials still had relatively large phase change enthalpy. Their phase change enthalpy could be correlated linearly with the loading of TD, but their phase change temperature was a little bite lower than that of pure TD. The thermal stability of the composite materials was close to that of pure TD. It appeared that there was no strong interaction between the Ag nanoparticles and the TD. Furthermore, the experiment results indicated that the Ag nanoparticles dispersed uniformly in the materials, occurred in the forms of pure metal.     

β-萘磺酸掺杂聚苯胺纳米粒子的固相反应法制备及其表征

利用固相反应法制备了 β 萘磺酸掺杂的聚苯胺纳米粒子 ,并以红外光谱 (FTIR) ,扫描电子显微镜(SEM) ,透射电镜 (TEM) ,X 射线衍射 (XRD)以及粉末微电极等测试方法对其进行了表征 .结果表明 ,固相反应法合成的 β 萘磺酸掺杂聚苯胺粒子直径为 30～ 5 0nm ,聚苯胺分子链排列有序 ,晶化率较好 .粉末微电极的循环伏安测试表明 ,β 萘磺酸掺杂聚苯胺有较好的电化学活性 .     

铂纳米粒子和锰卟啉修饰的聚苯胺新材料的制备及表征

借助循环伏安电化学聚合制备了聚苯胺(PANi)/MnT1239卟啉复合材料,再利用还原恒电位沉积法负载铂纳米粒子(Pt NP),最终制备了聚苯胺/MnT1239卟啉/铂纳米粒子复合材料.电沉积铂之后聚苯胺/MnT1239卟啉材料发生明显样貌变化,棒状结构平均直径从90 nm增加到200 nm,材料具有较大的表面积,空间可负载性好.铂纳米粒子平均尺寸在20 nm,附着均匀,氧化峰电流在0.2 V处达到7.4 mA,电化学性能优良.     

Synthesis and Characterization of Polyaniline/Partially Phosphorylated Poly（vinyl alcohol） Nanoparticles

The polyaniline/partially phosphorylated poly（vinyl alcohol）（PANI/P-PVA） nanoparticles were prepared by the chemical oxidative dispersion polymerization of aniline monomer in 0.5 mol/L HC1 aqueous media with the partially phosphorylated poly（vinyl alcohol） （P-PVA） as the stabilizer and co-dopant. The PANI/P-PVA nanoparticles were characterized by transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, thermal gravimetric analysis （TGA）, X-ray diffraction （XRD）, electrical conductivity measurements and re-dispersion stability testing. All the results were compared with the properties of the conventional polyaniline in the emeraldine salt form （PANI ES）. It was found that the feeding ratio of P-PVA obviously affected the morphology, re-dispersion stability and electrical conductivity of the PANI/P-PVA nanoparticles. When the feeding ratio of P-PVA ranged from 40 wt% to 50 wt%, the PANI/P-PVA nanoparticles showed spherical shape with good uniformity, significant re-dispersion stability in aqueous media and good electrical conductivity.     

Influence of silver-decorated multi-walled carbon nanotubes on electrochemical performance of polyaniline-based electrodes

In this work, silver (Ag) nanoparticles were deposited on multi-walled carbon nanotubes (MWNTs) by chemical reduction while Ag-decorated MWNTs (Ag-MWNTs)/polyaniline (PANI) composites were prepared by oxidation polymerization. The effect of the Ag incorporated into the interface of the composites on the electrochemical performance of the MWNTs/PANI was investigated. It was found that highly dispersed Ag nanoparticles were deposited onto the MWNTs, and the Ag-MWNTs were successfully coated by PANI. According to cyclic voltammograms, the Ag-MWNTs/PANI exhibited significantly increased electrochemical performances compared to MWNTs/PANI and the highest specific capacitance obtained of MWNTs/PANI and 0.15 M Ag-MWNTs/PANI was 162 F/g and 205 F/g, respectively. This indicated that Ag nanoparticles that were deposited onto the MWNTs caused an enhanced electrochemical performance of the MWNTs/PANI due to their high electric conductivity, which resulted in an increase of the charge transfer between the MWNTs and PANI by a bridge effect.     

Novel polyaniline/titanium nitride nanocomposite: controllable structures and electrical/electrochemical properties

We first present the preparation of a new class of polyaniline (PANI)/titanium nitride (TiN) nanocomposites by in situ chemical polymerization in the presence of TiN nanoparticles. It was found that nanocrystalline TiN with an average diameter of approximately 20 nm incorporated and dispersed homogeneously within the polymer matrix, leading to enhanced conductivity and electrochemical activity. The interaction between nanocrystalline TiN and the polymer matrix was characterized by XRD, FTIR, and UV-vis spectra. Interestingly, the morphology and structure of the PANI/TiN were controlled by the content of TiN nanoparticles in the composites. Structural changes are observed at TiN > or = 30 wt %, where the in situ synthesis results in rod-shape composite particles. The electrical and electrochemical properties of the nanocomposites were also affected by the structure. The mechanisms of the property changes with the TiN contents are discussed. The structural difference was used to explain the different activation energies for the conductance process in emeraldine base (EB)/TiN composites.     

Thermal and electrical conduction behavior of alumina and multiwalled carbon nanotube incorporated poly(dimethyl siloxane)

Alumina particles were incorporated in poly(dimethyl siloxane) (PDMS) matrix in company with multiwalled carbon nanotube (MWCNT) for improving the thermal and electrical conductivities. The concentration of MWCNT was increased from 0 to 10 wt% to PDMS at fixed amounts of alumina (200 and 300 wt% to PDMS). Thermal conductivity of PDMS composites was increased with the increasing amount of MWCNT and the excellent dispersibility of the incorporated pristine MWCNT was achieved. Thermal and electrical conductivities of the composites were increased with the increasing concentration of the alumina because the alumina particles help disperse MWCNT within the PDMS matrix due to the ball milling effect during compounding. The properties of the alumina and MWCNT incorporated PDMS composites were investigated in terms of the curing characteristics, electrical conductivity, and thermal conductivity. The MWCNT/alumina incorporated composite showed the high electrical conductivity to the level of the semiconductor.     

聚苯胺/分级碳纳米管复合材料的制备与性能研究

在众多的导电高分子中，聚苯胺具有原料易得、合成简便、能进行快速与可逆的氧化还原反应、可储存高密度的电荷等优点，在能源、光电子器件、电容器、传感器、分子导线和分子器件，以及电磁屏蔽、金属防腐和隐身技术等领域有着诱人的应用前景．近年来，将导电聚苯胺用于超电容器，倍受人们的广泛关注．     

Low-temperature preparation of highly conductive thin films from acrylic acid-stabilized silver nanoparticles prepared through ligand exchange

The preparation of AcA-stabilized Ag nanoparticles and its application to make highly conductive thin films are reported. The AcA-stabilized Ag nanoparticles were prepared through a ligand exchange of original oleylamine (OLA)-coated Ag nanoparticles with acrylic acid (AcA), which acted as both an antisolvent and a modifying ligand during the ligand exchange process. Efficiencies of the ligand exchange as well as the properties of Ag nanoparticles were analyzed using various techniques including TEM, FT-IR, XPS, TGA, and UV-vis methods. The thin films were fabricated by annealing spin-coated AcA-stabilized Ag nanoparticles. Further, the effects of annealing temperature, time, and film thickness on both the film morphology and electrical conductivity have been investigated. In this work, due to the low boiling temperature of stabilizer (AcA) and adjustment of annealing conditions, high electrical conductivity was obtained for the Ag thin films. For example, when annealing at 175 °C for 30 min, a 70 nm thick film showed a maximum electrical conductivity of 1.12 × 10(5) S cm(-1). A conductive layer on a flexible polymer substrate (e.g., PET) sheet has been successfully prepared by annealing a spin-coated film at 140 °C for 30 min. The combined advantages of long-term stability of the AcA-stabilized Ag nanoparticles, low annealing temperature, and high conductivity of the prepared thin films make this relatively simple method attractive for applications in flexible electronics.     

Ag复合对LaCoO_3陶瓷热电性能的影响

<正>0引言热电材料是利用热电效应实现电能和热能相互转化的功能材料,在废热发电和无氟制冷等方面有广泛的应用前景。其中氧化物热电材料是近年来备     

Electrical and optical properties of an organic semiconductor based on polyaniline prepared by emulsion polymerization and fabrication of Ag/polyaniline/n-Si Schottky diode

The electrical, optical, and metal-semiconductor contact properties of the polyaniline prepared by emulsion polymerization have been investigated to obtain an organic semiconductor material. The obtained results suggest that the polyaniline (PANI) studied is an organic semiconductor material with optical band gap (E(g) = 2.21 eV) and room electrical conductivity (sigma(25) = 3.12 x 10(-2) S/cm) values. A Schottky diode with configuration Ag/PANI/n-Si was fabricated. The ideality factor and barrier height of Ag/PANI/n-Si diode at room temperature were found to be 4.59 and 0.38 eV, respectively. The obtained diode parameters change with temperature. The Richardson constant A* value for the Ag/PANI/n-Si diode was found to be 3.81 x 10(-4) A/cm(2).K. The Ag/PANI/n-Si diode is a metal-insulator-semiconductor-type device. The standard deviation, which is a measure of the barrier homogeneity, was found to be 0.14, indicating the presence of interface inhomogeneities. It can be concluded that the polyaniline prepared by emulsion polymerization is an organic semiconductor and Ag/PANI/n-Si configuration shows a Schottky contact.     

Synthesis and thermo-physical properties of water-based novel Ag/ZnO hybrid nanofluids

The comparative study on the thermo-physical properties of water-based ZnO nanofluids and Ag/ZnO hybrid nanofluids is reported in the present study. The outer surface of ZnO nanoparticles was modified with a thin coating of Ag nanoparticles by a wet chemical method for improved stability and heat transfer properties. The ZnO and Ag/ZnO nanofluids were prepared with varying volume concentration (??=?0.02–0.1%). The synthesized nanoparticles and nanofluids were characterized with different characterization methods viz., scanning electron microscopy, X-ray diffraction, dynamic light scattering, thermal conductivity measurement, and viscosity measurement. Results show that thermal conductivity of Ag/ZnO hybrid nanofluids is found to be significantly higher compared to ZnO nanofluids. The maximum thermal conductivity an enhancement for Ag/ZnO nanofluid (??=?0.1%) is found to 20% and 28% when it compared with ZnO nanofluid (??=?0.1%) and water, respectively.     

导电聚苯胺与Fe3O4磁性纳米颗粒复合物的合成与表征

对十二烷基苯磺酸(DBSA)掺杂的导电聚苯胺(PAn-DBSA)的氯仿溶液,在pH为中性的条件下,采用“修饰-再掺杂(Modification-re-doped)法”合成了含有Fe₃O₄磁性纳米颗粒的导电聚苯胺复合物的有机溶液.用FTIR,XRD,TEM,UV-Vis和SQUID等对所得复合物进行了表征,结果表明,该复合物呈现超顺磁性和半导体的导电性,并具有较好的透明性.     

A composite polyaniline/graphene–coated polyamide6 nanofiber mat for electrochemical applications

In this study, polyamide6 (PA6) nanofiber mats were fabricated through the electrospinning process. The nanofibers were coated by polyaniline (PANI) using the in situ polymerization of aniline in the presence of graphene oxide. The composite of the PANI/graphene oxide–coated nanofiber mat was treated with hydrazine monohydrate to reduce graphene oxide to graphene, and this was followed by the reoxidation of PANI. Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), wide angle X‐ray diffraction (WAXD), thermal gravimetric analysis (TGA), tensile strength tests, electrical conductivity measurements, cyclic voltammetry (CV), and charge/discharge measurements were conducted on the composite PA6/graphene nanofiber mats. It was found that the surface of the PA6 nanofibers was coated uniformly with the granular PANI and graphene oxide. Besides, the composite nanofibers showed good tensile and thermal properties. Their electrical conductivity and specific capacitance, when used as a separator in the cell, were 1.02 × 10^?4 S/cm and 423.28 F/g, respectively. Therefore, the composite PANI/reduced graphene oxide–coated PA6 nanofiber mats could be regarded as suitable candidates for application in energy storage devices.     

In-situ synthesis of 3D printable mono- and Bi-metallic (Cu/Ag) nanoparticles embedded polymeric structures with enhanced electromechanical properties

The interest of additive manufacturing with 3D printing increases day by day, which provides improved mechanical, electrical, magnetic and thermal properties of 3D parts. The production of 3D parts with the stereolithography (SLA) method, which allows it to be produced with high precision, resolution and complex geometries, distinguishes itself from other alternative additive manufacturing methods (FDM. SLS. LOM. LMD etc.). However, studies on the preparation of functional 3D polymer nanocomposites with the SLA method are quite limited. This study aims to produce silver (Ag) and/or copper (Cu) based 3D polymer nanocomposites for enhancing its mechanical strength, thermal stability and electrical conductivity. Mono and bimetallic (Cu/Ag) nanoparticles have been in-situ synthesized by selective irradiation of laser beam method using a commercial SLA device. In this method, metal (Cu/Ag) acrylate containing photocurable resin is not only cured but also leads to thermal decomposition of metal ions into nanoparticles to form functional 3D structures. The mechanical, electrical and thermal properties of polymer nanocomposites are characterized in detail. As a result of the analysis, the nanoparticles, with an average diameter of 25–55 nm, are well dispersed in the polymer matrix without agglomeration. The temperature at which 5% weight loss of Ag and Cu based polymer structures is measured as 179.3 °C while the glass transition temperature is found to be 223.81 °C. Most importantly, the resistance values are significantly decreased from 456.62 GΩ (Gigaohm) to 1.50 GΩ by increasing the amount of Ag addition at 3D polymeric structures. Therefore, this study allows the production of polymer nanocomposites not only in complex structures but also in desired properties especially for electrically conductive materials, capacitors and electronic applications.     

Synthesis of polyaniline/multiwall carbon nanotube composite via inverse emulsion polymerization

The composite of polyaniline (PANI) and multiwall carbon nanotube carboxylated through acid treatment (c‐MWCNT) was synthesized by chemical oxidative polymerization in an inverse emulsion system. The resultant composites were compared with products from aqueous emulsion polymerization to observe the improvements in electrical conductivity, structural properties, and thermal stability obtained by this synthetic method. Prior to the inverse emulsion polymerization, MWCNT was treated with a strong acid mixture to be functionalized with carboxylic acid groups. Carboxylic acid groups on surfaces induced selective dispersibility between polar and nonpolar solvents because of the increase of hydrophilicity. As the content of c‐MWCNT was increased, the electrical conductivity was increased by a charge transport function from the intrinsic electrical conductivity of MWCNT and the formation of a highly ordered dense structure of PANI molecules on the surface of c‐MWCNT. The images observed with electron spectroscopy showed the capping of c‐MWCNT with PANI. The growth of additional ordered structures of PANI/c‐MWCNT composite, which was observed through wide‐angle X‐ray diffraction patterns, supported the capping by PANI. It was observed that the doping of the composite had a significant relationship with the concentration of dodecylbenzenesulfonic acid (DBSA). The thermal stability of PANI composite was improved by the addition of c‐MWCNT; this was thought to be related with structure ordering by inverse emulsion polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2255–2266, 2008     

磁性聚苯胺纳米微球的合成与表征

报道了具有核壳结构的Fe3O4-聚苯胺磁性纳米微球的合成方法和表征结果.微球同时具有导电性和磁性能.在优化的实验条件下,可得到饱和磁化强度Ms为55.4 emu/g,矫顽力Hc为62 Oe的磁性微球.微球的导电性随着微球中Fe含量的增加而下降.微球的磁性能则随着Fe含量的增加而增大.Fe3O4磁流体的粒径和磁性聚苯胺微球的粒径均在纳米量级.纳米Fe3O4粒子能够提高复合物的热性能.实验表明,磁流体和聚苯胺之间可能存在着一定的相互作用,但这种相互作用较为复杂,难于研究     

Significant enhancement of electrical and thermal conductivities of polyethylene carbon nanotube composites by the addition of a low amount of silver nanoparticles

Electrically and thermally conductive high‐density polyethylene composites filled with hybrid fillers, multiwall carbon nanotubes (MWCNTs) and silver nanoparticles (Ag‐NPs), have been prepared in the melt state. The investigation of their electrical and thermal conductivities while comparing with high‐density polyethylene/MWCNT binary composites shows that the addition of only 3 vol% of Ag‐NPs does not reduce the electrical percolation threshold (P_c) that remains as low as 0.40 vol% of MWCNTs but leads to an increase in the maximum dc electrical conductivity of PE/MWCNT composites by two orders of magnitudes. Moreover, the association of both Ag‐NPs and carbon nanotube particles improved our composite's thermal conductivity. Copyright © 2014 John Wiley & Sons, Ltd.