磁场环境下不同质子酸掺杂对聚苯胺结构和电导率的影响

在磁场环境下,采用微乳液合成法,研究了质子酸种类、氧化剂和乳化剂种类等因素对苯胺聚合反应及产物性能的影响,并通过红外光谱、粒径分析、腐蚀电位等表征了PAn性能与结构。实验结果表明：磁场对苯胺聚合的影响是正向的。     

镨掺杂的聚苯胺及其性能的研究

以苯胺、硝酸镨合成了本征态聚苯胺和掺杂态聚苯胺.采用扫描电镜、导电测试仪、红外光谱、TGA和XRD等对产物进行表征.结果表明硝酸镨很好地掺杂于聚苯胺基体内,当硝酸错与苯胺的摩尔比为1:1.5时,产物的电导率较好,为0.015 5 S/cm.     

氧化剂浓度对漂珠/聚苯胺复合材料的制备及其性能影响研究

本文采用乳液聚合法制备了十六烷基三甲基溴化铵改性漂珠/聚苯胺复合材料(FAFB-HDTMA/PAn),利用FTIR、SEM对产物的结构与形貌进行分析,并讨论了不同氧化剂过硫酸铵(APS)浓度对FAFB-HDTMA/PAn复合材料的产物颜色及其电学性能的影响.实验结果表明:利用FTIR和SEM分析证明HDTMA对FAFB修饰改性成功,FAFB-HDTMA被PAn包覆;通过观察复合产物颜色可知,随着APS:An浓度比的增加,产物颜色更趋近于掺杂态PAn的颜色;利用四探针技术测试发现,聚苯胺的电导率随着改性粉煤灰漂珠(FAFB-HDTMA)的加入而降低了近100倍;利用LCR数字电桥测试发现,在100 kHz～2 MHz的频率范围内,FAFB-HDTMA/PAn复合材料的相对介电常数和介电损耗随外加频率的增大而减小,进而可知当APS::An浓度比为0.8时,FAFB-HDTMA/PAn复合材料的电导率和相对介电性能均为最优效果.     

不同质子酸掺杂对聚苯胺性能的影响

用化学氧化法合成了不同质子酸掺杂的聚苯胺,并研究了各种质子酸掺杂对聚苯胺产量、溶解性能和导电性能的影响。研究发现,在文章中选用的几种掺杂剂中,三氯乙酸掺杂的聚苯胺在电导率、产量和溶解性方面都具有明显的优势,尤其是在产量和溶解性能方面,优势更加显著。     

十二烷基苯磺酸掺杂聚苯胺的性能研究

用十二烷基苯磺酸 (DBSA)对本征态聚苯胺 (PAn)进行掺杂 ,得到溶解性、成膜性和光电性能俱佳的掺杂态聚苯胺。红外光谱研究表明 :DBSA掺杂PAn的吸收峰都向低频方向移动。探讨DBSA浓度、掺杂温度和时间以及洗涤滤液pH值对聚苯胺电导率的影响。结果表明 :当c(DBSA) =1 0mol/L ,T =32 3K ,t=8h ,洗涤滤液 pH =3时 ,聚苯胺的电导率为 0 90 9S/cm。紫外 -可见吸收光谱表明 ,掺杂态聚苯胺的吸收峰变宽而且发生红移。X射线衍射在 2θ =8 86°,1 7 7° ,2 1 4°和 2 6 7°处出现 4个较强的低角度衍射峰 ,表明DBSA掺杂的聚苯胺具有较强的结晶性能。     

十二烷基苯磺酸掺杂聚苯胺的制备及性能

用十二烷基苯磺酸（DBSA）的水溶液对化学合成的聚苯胺（PAn)进行掺杂,获得了导电的DBSA掺杂PAn(PAn-DBSA),通过对本征态聚苯胺（PAnEB)掺杂率的计算和电导率的测定,研究了DBSA用量及其溶液浓度对掺杂效果的影响,结果表明,当DBSA／PAnEB(摩尔比）小于0．1时,溶液浓度的影响很小,当DBSA／PAnEB大于0．2时,溶液浓度的影响非常大,而且,高浓度比低浓度对提高掺杂率和电导率更有利。热重分析表明,PAnEB,PAn-DBSA在空气中的热分解温度分别为350和250℃,表现出良好的热稳定性。     

聚苯胺盐的合成及导电性能研究

用对甲苯磺酸作为掺杂剂对聚苯胺(PANI)进行掺杂,合成了导电聚苯胺盐(ES)。研究了掺杂剂用量、模压压力、模压温度、氧化剂用量对聚苯胺盐电导率的影响。结果表明：随着掺杂剂用量的增加,PANI的电导率也在不断的增大;当ES所受压力较高时,电导率提高;高温使PANI电导率上升;氧化剂与苯胺的最佳配比为1：1。     

不同质子酸掺杂对聚苯胺合成与性能的影响

由化学氧化法制得的聚苯胺(PANI)被不同质子酸掺杂。研究盐酸(HCl)、硫酸(H2SO4)、樟脑磺酸(CSA)和十二烷基苯磺酸(DBSA)掺杂对PANI产率、溶解性以及电导率的影响。研究发现,HCl掺杂的PANI电导率为0.263 4 S/cm、产率可达到78.83%。还讨论不同HCl浓度和不同过硫酸铵/苯胺(APS/An)的物质的量比对HCl掺杂PANI产率和电导率的影响,当HCl的浓度达到1.2 mol/L、APS/An物质的量比为0.6时,PANI的电导率和产率均为最大值。     

磁场环境中电化学制备聚苯胺膜的性能研究

文章采用循环伏安法,在磁场环境中探讨了不同的磁场方向,磁场强度、镀膜电压、镀膜圈数等因素对聚苯胺（PANI）膜电化学性能的影响,并对PANI膜进行了电化学性能测试。结果表明,在磁场环境中,采用循环伏安法制备PANI膜的较优化工艺条件是：磁场方向与电场方向瓦棚垂直,磁场强度为0．4T,镀膜电压的范围是．0．2-0．9V,镀膜圈数为40圈。     

导电聚合物聚苯胺的制备与表征及导电性能的研究

在实验中采用苯胺在不同的酸性介质中,用过硫酸铵氧化聚合得到聚苯胺,发现其反应产率和聚苯胺的电导率都存在着较大的差异,并且发现酸的强度和氧化能力对聚苯胺的聚合有着较大的影响,并对聚苯胺进行了红外光谱和紫外可见光光谱分析与表征,表明聚苯胺主链结构经质子酸掺杂后由于电子的离域形成了共轭结构,从而使聚苯胺有良好的导电性能。     

Effects of static magnetic field on water at kinetic condition

Water was exposed for different times to weak static magnetic field (MF) generated from a stack of magnets (B = 15 mT) or from a single permanent magnet (B = 0.27 T) at flow conditions. The water conductivity and the amount of evaporated water were measured as a function of time following the application of MF. It was found that the MF decreases the water conductivity, which is inversely proportional to the flow rate, and increases the amount of evaporated water, even after the water's distillation. The effects are due to the hydrogen bond network strengthening and the perturbation of gas/liquid interface from the air nanobubbles in the water.     

Influence of plasticizers (DOP and CNSL) on mechanical and electrical properties of SBS/polyaniline blends

Electrically conductive blends based on polyaniline-dodecylbenzene sulfonic acid (Pani.DBSA)/styrene-butadiene-styrene (SBS) block copolymer have been prepared in the presence of different plasticizers such as dioctyl phthalate (DOP) and cashew nut shell liquid (CNSL). The products were characterized by ultraviolet-visible (UV-vis) spectrometry, scanning electron microscopy, X-ray diffraction, electron paramagnetic resonance (EPR) and resistivity measurements. The presence of DOP resulted in an increase of the electrical resistivity whereas the increasing concentration of CNSL resulted in a decrease of electrical resistivity. In the latter case, the presence of cardanol, a phenol-type compound in CNSL, may be responsible for the improved electrical performance, probably because of a secondary doping process, which changes the molecular conformation of Pani.DBSA chains from “compact coil” to “expanded coil”. In addition, CNSL contributes to the formation of cocontinuous-type morphology with conducting pathways in larger extension. EPR studies also showed an increase of the polaron mobility as the amount of CNSL in the blend increases.     

Influence of the nanostructure on charge transport in polyaniline films

Two kinds of polyaniline films with different microstructures were prepared and investigated. One of the films was prepared with polyaniline having nanofiber structure, which was synthesized by rapidly mixed reaction; and the other was prepared with polyaniline having granular particle structure, synthesized by conventional chemical oxidation method. The spectroscopic, electrochemical, and transport properties of the two kinds of films were studied with an interest in an influence of film microstructure on mobilities of charge carriers in polymer films. A clear difference was observed in the mobility versus oxidation level plot between the two kinds of polyaniline films. The results show that nanofiber structure of polyaniline film enhances mobilities, but affect little features of the mobility change induced by oxidation, which implies that although the nanofibers structure facilitates the charge transport in neutral or oxidized films, but it is irrelevant to the evolution of metallic conduction in polyaniline films.     

Electrically conductive hydrogel composites made of polyaniline nanoparticles and poly(N-vinyl-2-pyrrolidone)

A novel electrically conductive composite material, consisting of polyaniline (PANI) nanoparticles dispersed in a polyvinyl pyrrolidone (PVP) hydrogel, was prepared ‘in situ’ by water dispersion polymerisation (DP) of aniline using PVP as steric stabiliser, followed by γ-irradiation induced crosslinking of the PVP component. Conversion yield of aniline into PANI particles was determined via HPLC and gas chromatography, while structural confirmation of the synthesised polymer was sought by FTIR. Morphology and dimensions of PANI particles into the coloured, optically transparent hydrogel was determined by electronic microscopy; moreover, swelling behaviour of composite hydrogels in different buffer solutions was investigated by gravimetric measurements and compared to that of pure PVP hydrogels.Cyclic voltammetry experiments were carried out both on these hydrogels and on the parent aqueous dispersions, at different pH values of the suspending/swelling medium, while conductivity of the composite hydrogels was derived from Impedance Spectroscopy; in both cases results were compared to those relative to hydrogels containing commercial-grade PANI particles.     

Ultrafine nano-colloid of polyaniline

We report a synthesis of polyaniline (PANI) suspension of particles with size of about 2-3 nm. This nano-colloid was obtained by aniline oxidative polymerization in dilute and semi-dilute solutions of sodium poly(styrene sulfonate) (PSSNa) with molecular weight equal to 6800 g/mol or higher. The ionic strength of the solution was about 1×10⁻² mol/l, which corresponds to aniline (and, respectively, PANI) concentration lower than 4.6×10⁻² mol/l in 5 M solution of formic acid. To the best of our knowledge, it is the first communication dealing with preparation of particles with a molecular scale dimensions, using a rigid backbone polymer with a very strong intermolecular interactions. Important modification of the electronic properties of such dispersed PANI, compared to those of the well-known bulk PANI, was observed.     

Some mechanisms concerning the electrical conductivity of magnetorheological suspensions in magnetic field

Iron carbonyl is decomposed, at the temperature of 473 K ± 10%, into a liquid matrix formed of silicone oil and stearic acid. For 3.703% and 1.886% stearic acid, magnetorheological suspensions (MRSs) are obtained. The iron particles in MRSs have the mean diameter of 0.356 μm. Magnetoresistors are achieved from MRSs with the dimensions of diameter and length equal to 5 mm. In longitudinal magnetic field, the resistance of the magnetoresistors is measured. Assimilating the resistance of the magnetoresistors with that of a linear resistor, the conductivity σ of MRS is determined. The duration t_c of onset of σ is determined. It is observed that t_c is considerably influenced by the intensity of the magnetic field applied and by the composition of MRSs. Experimental data are discussed, too.     

Effect of dopant and oxidant on the electrochemical properties of polyaniline/graphite nanoplate composites

Optimizing the synthesis parameters of polyaniline/graphite nanoplate (PANI/GNP) composite is essential to the final electrochemical performance. Herein, the electrochemical properties of PANI/GNP composites, prepared by in situ chemical polymerization using varying amounts of different oxidants, with or without the addition of 4‐dodecylbenzenesulfonic acid (DBSA) as dopant, were investigated. Cyclic voltammetric results suggested that a stoichiometric amount of the oxidant iron chloride (FeCl₃) was beneficial to the electrochemical properties of the composites. The use of ammonium persulfate (APS) instead of FeCl₃ as oxidant largely increased the actual PANI content, conductivity and specific capacitance of the PANI/GNP composites. The dopant DBSA increased the conductivity of the PANI/GNP composites but did not show a positive effect on the electrochemical behavior. The cyclic voltammograms of the PANI/GNP composites indicated that the pseudocapacitance of PANI contributes more than the electrical double‐layer capacitance of GNP to the capacitance of the composites, while the presence of GNP plays an essential role in the rate capability of the composites. In this study, PANI/GNP (1:1) composite synthesized with an APS to aniline molar ratio of 1 showed a balanced combination of high specific capacitance (180.5 F g^?1 at 20 mV s^?1) and good rate capability (78% retention at 100 mV s^?1). © 2018 Society of Chemical Industry     

Liquid crystalline epoxy resin based on biphenyl mesogen: Effect of magnetic field orientation during cure

A biphenyl based epoxy monomer, 4,4′-diglycidyloxybiphenyl (BP), was synthesized and cured with a tetra-functional amine, sulfanilamide (SAA), to obtain a liquid crystalline epoxy network. The curing behavior of BP with SAA was studied using differential scanning calorimetry, polarized optical microscopy, and parallel plate rheology. Macroscopic orientation of the liquid crystalline epoxy resins (LCERs) was achieved by curing in a high strength magnetic field, and quantified by an orientation parameter determined with wide angle X-ray diffraction. The effects of orientation on the glass transition temperature, coefficient of thermal expansion, and dynamic mechanical properties of the LCERs were investigated. The results reveal that the formation of the liquid crystalline phase has a dramatic influence on the curing reaction, leading to a decrease in viscosity of the reacting system. Oriented LCERs exhibit anisotropic thermal expansion behavior and significant improvements of thermomechanical properties.     

Effect of secondary dopants on electrochemical and spectroelectrochemical properties of polyaniline

Polyaniline (PANI) was doped with poly(styrene sulfonic acid) (PSS) via doping-dedoping-redoping procedure. Incorporation of PSS in PANI resulted modifications in electrochemical and electrochromic properties, morphology and polymer structure of the polymer film as evidenced by the results of cyclic voltammetry, in situ UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis and conductivity measurements. PANI doped with PSS was found to have a cross-link/branched structure with a minimum degradation product. The absence of degradation products improves the electrochemical, electrochromic properties and thermal stability of the PANI layer for electrochromic applications.