pH-sensing properties of poly(aniline) ultrathin films self-assembled on indium-tin oxide

The structural and functional properties of ultrathin (<5 nm) poly(aniline) (PANI) films deposited on indium-tin oxide (ITO) have been investigated using electrochemical and attenuated total reflection (ATR) spectroscopy methods. Layer-by-layer (LbL) self-assembly was used to form films composed of one and two bilayers of PANI and poly(acrylic acid) (PAA), as well as single PANI layers of approximately monolayer thickness. PANI deposited on an ITO electrode is electroactive at neutral pH, both with and without codeposition of an acid dopant such as PAA. In the absence of PAA, it is hypothesized that the acidic surface groups on ITO can function as the counterion. The pH response of PANI single layer, (PANI/PAA)(1), and (PANI/PAA)(2) films was examined using both potentiometry and ATR spectroscopy. Near-Nernstian potentiometric responses over pH 3-9 were observed for all three types of films, consistent with the weak acid-base behavior expected of polymers assembled in a LbL film. The ATR spectral sensitivity to pH increases as the number of layers in the film increases, with the highest sensitivity achieved by monitoring the absorbance at 800 nm (predominately due to the emeraldine salt form) of (PANI/PAA)(2) films. Codeposition of PANI and PAA appears to produce a wide distribution of strengths of acidic and basic sites in the film and thus a large linear dynamic range, up to six pH units. The water contact angle of (PANI/PAA)(2) is approximately 16 degrees, which is considerably more hydrophilic than either the PANI single layer or (PANI/PAA)(1) films ( approximately 40 degrees ). This film is shown to be a suitable substrate for deposition of a planar supported phospholipid bilayer. The supported membrane is highly impermeable to protons, which makes this architecture useful for monitoring transmembrane charge transport.     

高强度聚苯胺-聚丙烯酸/聚丙烯酰胺导电水凝胶的制备与性能

将导电聚合物引入到水凝胶网络中的导电高分子基导电水凝胶,因结合了水凝胶的三维网络结构、良好的生物相容性、优异的力学性能等和导电高分子良好电学性能等优点而被广泛研究,特别是以聚苯胺(PANI)为导电高分子的导电水凝胶.但PANI不溶于水,因此很难制备PANI基导电水凝胶.本文以制备高强度PANI基导电水凝胶为目的,尝试将...     

Fabrication of conductive network formed by polyaniline-ZnO composite on fabric surfaces

A conductive network consisting of polyaniline (PANI) and PANI/nm-ZnO immobilized on the surfaces of poly(ethylene terephthalate) (PET) fabrics was synthesized by a route involving a wet-chemical technique and in-situ chemical oxidative polymerization procedures. Morphological, structural, thermal and electrical properties of the PET fabrics modified with PANI-ZnO composites were analyzed. X-ray diffraction (XRD) measurements of the composites revealed that the crystal structure of incorporated ZnO undergone a weak distortion during the polymerization reaction and the XRD pattern of PANI was predominate. Attenuated total reflection Fourier transform infrared spectroscopic studies indicated the presence of interaction between ZnO nanorods and molecular chains of PANI in the ZnO/PANI layers. Field emission scanning electron microscope images implied the thin composite layers showed a submicro-sized rod like network and the homogeneous distribution on the substrates. Thermogravimetric studies exhibited that the PET-ZnO/PANI composite had a higher thermal stability than anyone of PET and PET-PANI. The surface resistance of ZnO/PANI conductive films was found to be smaller than the PANI film, which was declined as aniline concentration in adsorption bath increased and reached a relatively low value when Zn(NO₃)₂ concentration was at 0.03 mol/L in the precursor solution.     

SPS/PANI复合颗粒的制备与性能研究

掺杂态聚苯胺(PANI)在碱性环境下易脱掺杂是影响其应用的一个不利因素．本文通过对乳液聚合的聚苯乙烯(PS)颗粒进行磺化．得到表面磺化的PS颗粒(SPS)．然后在颗粒表面原位合成PANI．进一步得到表面由磺酸掺杂的PANI包覆的复合颗粒(SPS／PANI)。研究了PANI的原位聚合过程、复合颗粒的电导率和复合颗粒的耐碱性等．结果表明这种复合颗粒在弱碱性(pH=7～9)介质中的稳定性得到显著改善。     

Preparation and characterization of polyaniline-copper composites by electrical explosion of wire

Polyaniline-copper composites with a polyacrylic acid (PAA) were synthesized by electrical explosion of wire. Polyaniline (PANI) and PAA were put into the explosion medium, deionized water (DIW) and ethanol, stirred for 24 hrs and sonicated for 2 hrs. These solutions were used as base liquids for explosion process to fabricate Cu nanoparticle. Optical absorption in the UV-visible region of PANI and PANI/PAA-Cu composites was measured in a range of 200-900 nm. X-ray diffraction was used to analyze the phase of the composites. XRD pattern showed the PANI was amorphous and copper was polycrystalline. Two phases of Cu and Cu2O were formed in aqueous solution while single Cu phase was obtained in ethanol solution. Field emission scanning electron microscope was used to observe the microstructure of the composites. The synthesized composites were extensively characterized by Fourier Transform Infrared (FTIR) spectroscopy and electrical measurements.     

导电高分子聚苯胺及其应用

聚苯胺 (PANI)是研究最为广泛的导电高分子材料。本文介绍了导电高分子的掺杂原理和常用方法 ,以及PANI的结构与性能 ,综述了PANI的一些主要应用研究和领域     

Polyaniline/silver nanowire cotton fiber: A flexible electrode material for supercapacitor

The silver nanowire (AgNWs) / cotton fiber was used as a conductive substrate with high conductivity charge transfer. Then the polyaniline (PANI) molecular chain was fixed on the AgNWs / cotton fiber by in-situ polymerization to prevent its dedoping and improve its cyclic properties. Thus the flexible capacitor electrode material with conductive, specific capacity and cyclic properties was obtained. The results showed that when the mass ratio of KH-560 to AgNWs/cotton fiber was 3:1, the grafting rate of epoxide group on the modified AgNWs/cotton fiber was the highest. When the mass ratio of aniline to modified AgNWs cotton fabric was 3:1, the PANI content of in-situ polymerization on the fabric surface was the highest, 20.83%. The specific capacity of PANI/AgNWs/cotton fiber electrode material was the highest, 154 F/g, after 5000 cycles of charging and discharging, the specific capacity could keep 96%. It is worth mentioning, the introduction of PANI and AgNWs could significantly improve the wear resistance of cotton fiber, the friction resistance of the cotton fabric increased to 36,000 times. It is provided a new idea for design a flexible capacitor electrode material integrating electrical conductivity and cyclic stability.     

Hierarchical architecture of ultrashort carbon nanotubes/polyaniline nanocables coated on graphene sheets for advanced supercapacitors

Multilayer super-short carbon nanotubes (SSCNTs) could be prepared by tailoring raw multiwalled carbon nanotubes (MWCNTs) with mechanical-stirring and ultrasonic oxidation-cut method. The SSCNTs/polyaniline/reduced graphene oxide (SSCNTs/PANI/RGO) ternary hybrid composite was fabricated by reducing SSCNTs/PANI/GO precursor prepared by self-assembly from the complex dispersion of graphene oxide (GO) and the as-prepared SSCNTs/PANI nanocables, followed by redoping and reoxidation of the reduced PANI to restore the conducting structure of PANI in the ternary composite. The microscope images indicated that SSCNTs/PANI nanocables could uniformly distribute in the conductive network of graphene sheets and prevent the agglomeration of graphene. Such the hierarchical structure perfectly facilitates the contact between PANI for faradaic energy storage and electrolyte ions, and efficiently utilizes the double-layer capacitance of SSCNTs and graphene sheets at the electrode–electrolyte interfaces. The maximum specific capacitance of the SSCNTs/PANI/RGO composite achieved 845 F g^?1, which was much higher than that of pure PANI and SSCNTs/PANI nanocables. Moreover, the ternary composite also showed the good cycling stability, retaining about 96% of its initial capacitance after 1000 cycles because of the synergistic effect and conductive network of SSCNTs/PANI nanocables and graphene sheets. Therefore, the combined effects between SSCNTs/PANI nanocables and graphene sheets taking advantage of both charging and faradaic processes could readily explain the excellent electrochemical performance for supercapacitors.     

A thin PANI and carrageenan–gold nanoparticle film on a flexible gold electrode as a conductive and low-cost platform for sensing in a physiological environment

In this work, we report the production of a layer-by-layer (LbL) film of gold nanoparticles stabilized with carrageenan (carr-AuNPs) interspersed with a conductive polyaniline (PANI) layer. Conventionally, PANI has poor electroactivity in physiological buffers, limiting its using in electrochemical biosensors. The films were prepared on low cost and easy to manufacture flexible gold electrodes (FEAu). Two adsorption sequences were tested for production of the films—PANI/carr-AuNP and carr-AuNP/PANI. The gold nanoparticle size and colloidal stability were characterized. The films were characterized by cyclic voltammetry, UV–visible spectroscopy and atomic force microscopy. The results showed the synergistic effects of the carr-AuNPs (120 nm) and PANI, which improved both the electrochemical response and the stability of the conductive polymer in physiological medium by three times. The presence of the carr-AuNPs in the film caused a significant increase in roughness of the FEAu-modified electrode compared to that of an unmodified electrode, resulting in an increased active electrode area. Studies of film growth by UV–Vis spectroscopy indicated that the deposition mechanisms of both films involved an auto-regulating adsorption process, with the same amount of material adsorbed in each coating step. The PANI/carr-AUNP film showed considerable improvement in stability and conductivity compared to PANI-only films in the physiological environment, which confers advantages for use as a biosensor.     

真空蒸发沉积聚苯胺—TCNQ复合薄膜的STM研究

利用扫描隧道显微镜对真空蒸发沉积的聚苯胺－ＴＣＮＱ（ＰＡＮＩ－ＴＣＮＱ）复合薄膜、纯聚苯胺薄膜及纯ＴＣＮＱ薄膜试样进行了对比分析。研究发现,纯ＰＡＮＩ薄膜和纯ＴＣＮＱ薄膜都是绝缘膜,而用ＴＣＮＱ挽杂获得具有较高导电特性的ＰＡＮＩ－ＴＣＮＱ复合薄膜。而且与表面粗糙不连续的ＰＡＮＩ薄膜和ＴＣＮＱ薄膜相比,ＰＡＮＩ－ＴＣＮＱ复合薄膜易形成较大面积的表面结构完善的连续膜。傅里叶变换红外光谱（ＦＴＩＲ）分析     

Scavenging phenomenon and improved electrical and mechanical properties of polyaniline–divinylbenzene composite in presence of MWCNT

A semi-doped polyaniline (PANI)–dodecylbenzenesulfonic acid (DBSA) complex is added with a suspension of multiwall carbon nanotubes (MWCNT)–divinylbenzene (DVB) to prepare PANI–MWCNT based thermosetting conductive resin system. Firstly, unreinforced nanocomposites with various loading of MWCNT are prepared. Continuous improvement in the electrical conductivity is observed with increasing MWCNT loading in the composite, while improvement in the mechanical properties is observed only up to 0.2 wt% MWCNT loading. On further MWCNT loading, the decrease in mechanical properties is observed. Flexural strength increased by 18% with 0.2 wt% of MWCNT in the unreinforced nanocomposite while electrical conductivity increased continuously to 0.68 S/cm (at 0.5 wt% of MWCNT loading) from 0.25 S/cm (neat sample). DSC and TGA analysis show that MWCNT effectively contributed to enhance the scavenging effect of PANI, affecting degree of DVB polymerization at higher loading of MWCNT. Samples were characterized by FTIR analysis. DMA analysis is also performed to understand the mechanical behavior of the cured unreinforced nanocomposite under dynamic loading. SEM observation has been employed to understand the dispersion behavior of MWCNT into the matrix. PANI-wrapping behavior on MWCNT is observed from the SEM images. Wrapping of PANI on MWCNT increased doping state and surface area of PANI which subsequently contribute to the increased scavenging behavior of PANI at higher MWCNT loading. A structural thermosetting nanocomposite with electrical conductivity of 0.68 S/cm, flexural modulus of 1.87 GPa and flexural strength up to 35 MPa is prepared. In addition, PANI–DBSA/DVB matrix with MWCNT is also used to impregnate carbon fabrics to prepare highly conductive CFRPs. A CFRP with 1.67 S/cm electrical conductivity in through-thickness direction and 328 MPa flexural strength is obtained with the addition of 0.2 wt% MWCNT into the resin system.     

聚苯胺及其伪装应用研究进展

导电高分子聚苯胺(PANI)因其独特的掺杂机制和多样化的结构特征,而表现出一系列特殊的光、电等物理性能;PANI容易与其他有机或无机材料复合的特点,使它的功能与用途更加丰富广泛。因此,PANI一直是导电聚合物研究的热点。本文综述了近些年国内外关于PANI的合成、性能表征及其改性等方面的研究进展;随后重点分析了PANI在可见光、红外、雷达波等频段特性研究;最后,展望了PANI通过在分子结构设计、纳米材料复合、器件结构等方面研究及改进,解决实用中柔韧性、兼容性、寿命、功耗等方面难题,将会在光学自适应伪装、多频段复合隐身伪装等智能伪装领域发挥重要作用。     

Electrical and morphological characterization of polyaniline/sulfonated poly(arylene ether sulfone) composite films

Electrically conductive polyaniline/sulfonated poly(arylene ether sulfone) (PANI/BPS-35) composites were prepared. The influence of humidity and temperature on electrical conductivity of 20 wt% polyaniline containing composite films was tested. The conductivity increment from 17 mS/cm to 44 mS/cm was observed when the temperature increased from 24 °C to 80 °C at 50% relative humidity (RH). The maximum conductivity was 53 mS/cm at 80 °C and 70% RH. Aluminum (Al) and gold (Au) contacts were deposited onto PANI/BPS composite films and their contact properties have been investigated. While Al contacts behave like Schottky type contact, Au contacts showed nearly ohmic characterization. Scanning electron microscopy technology was used to investigate the morphology of PANI/BPS-35 composite films.     

In-situ production of electrically conductive fibres in polyaniline-SBS blends

Blending of electro-conductive monofilaments with more traditional insulating materials is a promising approach for the production of composites for applications in static dissipative packaging and in industrial textiles. Accordingly, we report on a favourable method for manufacturing these kinds of material which involves generating the fibres in-situ, that is, during the actual forming process. Electrically conductive polyaniline (PANI) was thermally blended with polystyrene-polybutadiene-polystyrene (SBS) at different weight compositions. The resultant blends were capillary extruded in order to induce a drawing process in the dispersed phase (PANI) of the blend and hence, the in-situ formation of PANI fibres within the above mentioned polymeric matrix. Microscopic analysis on the extrudates revealed that PANI was deformed during the process to produce elongated structures, i.e. ellipsoids or even short fibres, in the blends. Electrical measurements were performed and it was found that blending SBS with no more than 20 weight percent of PANI could produce an electrically conductive composite with a good level of conductivity. The relationship between the volume conductivity and content of PANI in the PANI-SBS blends, was found to be characteristic of a percolation system, with a threshold as low as 5 weight percent of PANI.     

原位聚合法制备PANI/EP导电防腐蚀涂层

传统方法制备的聚苯胺防腐蚀导电涂层,聚苯胺易下沉,使涂层电导率差.为此,借用原位聚合方法制备了聚苯胺/环氧树脂(PANI/EP)复合防腐蚀涂层.利用相应的性能测试方法检测和比较了不同反应条件下(如苯胺单体用量、引发剂的用量、酸量、聚合时间)合成的聚苯胺复合涂层的导电性能,并将其与传统方法制备的涂层进行了比较.结果表明:降低了氧化剂、酸的用量;因为降低了聚苯胺的粒径而减轻了聚苯胺粒子在涂层中的下沉,从而提高了涂层的导电性能,电导率达到1.6×10-2S/m.     

Preparation of polyaniline nanofibers and nanoparticles via simultaneous doping and electro-deposition

We present a new post-synthetic method for producing different nano-structures of Polyaniline (PANI), especially nano-fibers and nano-particles of varying doping (oxidation) states, by simultaneous doping and electro-deposition from electrolyte solutions of undoped PANI (Emeraldine bases) and p-toluenesulphonic acid using constant applied voltage and varying deposition time. High Resolution Transmission Electron Microscopy analysis reveals that during the initial doping-dominated stage continuous connected conductive PANI Emeraldine salt nano-fibers of diameter less than 50 nm are formed while in the later deposition-dominated stage, 30-50 nm sized isolated dispersed nano-particles of non conductive Leuco-Emeraldine are formed.     

Preparation process and properties of LiCoO2/PANI/dodecylbenzenesulfonate composite electrode materials

Composite materials that combine the lithium exchanging material LiCoO₂ and the conductive polymer poly(aniline) (PANI) have been investigated regarding their possible application to electrode materials of lithium batteries. Such composite materials have been prepared by means of polymerization of aniline in acidic suspensions of LiCoO₂ particles. PANI was synthesized by oxidative polymerization of aniline by ammonium persulfate in the presence of sodium dodecylbenzenesulfonate (SDBS) as a micellar template and dopant. The composite material consisted in LiCoO₂ particles dispersed in a continuous matrix of PANI. The ribbon-like morphology of the powdered material was distinctly different of the morphologies of the parent materials. The conductive material had conductivity close to that of PANI because the LiCoO₂ content of the composite material was low. The presence of the poorly conductive inorganic phase caused a significant loss of conductivity, showing that LiCoO₂ blocked electronic transfers between PANI crystallites. Ammonium persulfate caused the loss of lithium from LiCoO₂ when it was used at high concentration in the polymerization recipe. In this case a new phase made of Co₃O₄ formed by chemical decomposition of Li_xCoO₂. Thin films prepared from stable suspensions of composite materials in water show comparable electrical performance to that measured for bulk materials.     

PVA/PAA复合膜电响应特性的研究

通过研究PVA/PAA复合膜红外光谱特性,扫描电镜分析,及电场作用下膜通量的变化,阐明了PVA/PAA复合膜的电响应特性和规律。研究结果表明:制备的PVA/PAA复合膜中PVA与戊二醛已经发生交联反应形成酯键;-COOH基团的离子化是产生电响应的必要条件。随着PAA含量的增加,膜通量也明显的增加,表明体系中离子基团的数量(浓度)能够强烈影响PVA复合膜的直流电响应性;随着电场强度的增大,膜通量增加;在离子强度小于0.01mol/L时,膜通量随离子强度的增加而增加,但当离子强度大于0.01mol/L时,膜通量则呈现下降的趋势。在实验条件下,比较理想电响应条件为PVA∶PAA=1∶1,溶液离子强度为0.01mol/L。     

Synthesis and electrical properties of polymer composites with polyaniline nanoparticles

Nano-sized polyaniline (PANI) particles dispersed in aqueous solution were prepared using both poly(vinyl alcohol) (PVA) and poly(styrene sulfonic acid) (PSSA) as polymeric stabilizers. Size of the spherical PANI particle synthesized using PVA with a HCl dopant (PANI-HCl/PVA) was about 150 nm in diameter, and that with PSSA (PANI-PSSA) was about 50 nm, with a uniform size distribution. Doping level of the PANI-PSSA measured by UV–visible spectrometer was higher than that of PANI-HCl/PVA. The PVA based composite films using both PANI-HCl (PANI-HCl/PVA) and PANI-PSSA (PANI-PSSA/PVA) were prepared by a casting method for different PANI content and their electrical conductivities were measured. A percolation threshold of PANI concentration for conductivity of composite was found only around 10 wt.% of PANI for the PANI-PSSA/PVA, and furthermore, the PANI-PSSA/PVA became more conductive above the threshold point than PANI-HCl/PVA.     

聚苯胺导电复合膜电化学制备及其性能

采用电化学氧化聚合法,以硫酸和高氯酸为掺杂剂,制备出聚苯胺（PANI）/聚乙烯醇（PVA）导电复合膜,在此复合膜上再沉积一层很薄的银层,制备出具有高导电性的复合膜。研究了苯胺聚合时间、银沉积电流密度及银沉积时间和拉伸处理对复合膜电导率的影响。采用扫描电镜、X射线衍射对复合膜进行表征,并对复合膜导电机理进行解析。结果表明制备的PVA-PANI复合膜电导率可达4.2S.cm-1,再经沉积薄层银后,其电导可显著提高至1136 S.cm-1。最优条件下制备的PVA-PANI复合膜为纤维状,银在此复合膜上沉积呈针状;PVA-PANI复合膜具有一定的结晶度,经拉伸后,其结晶度增大,复合膜电导得到提高,PVA-PANI复合膜具有良好力学性能。复合膜导电的基本原理是PANI与PVA互穿网络,并与银形成了三维导电网络。