Synthesis and characterization of polyaniline–zirconium dioxide and polyaniline–cerium dioxide composites with enhanced photocatalytic degradation of rhodamine B dye

For the first time, chloroform and 2-butanol were used as solvent systems for the preparation of ZrO₂–PANI and CeO₂–PANI composites. Solubility of the synthesized composites was studied in chloroform, N-methyl-2-pyrrolidinone (NMP), and in mixture of toluene?+?2-propanol (2:1). XRD and cyclic voltammetry data showed that the ZrO₂–PANI and CeO₂–PANI composites possess both crystalline and amorphous domains indicating some sort of conductivity. TGA results showed that ZrO₂–PANI composite have a better thermal stability than pure PANI; however, CeO₂–PANI composite has lower thermal stability than pure PANI. The conjugated unsaturated structure of PANI is responsible for the enhanced photocatalytic properties of ZrO₂–PANI and CeO₂–PANI. Photocatalytic results showed that, at photolysis time of 60 min, rhodamine B (RhB) dye was degraded up to 34 and 35% by ZrO₂–PANI and CeO₂–PANI, respectively. The degradation products of RhB were quantified by LC–MS and GC–MS, and accordingly, a detailed pathway was proposed.     

Thermal stability of several polyaniline/rare earth oxide composites (I): polyaniline/CeO<Subscript>2</Subscript> composites

Polyaniline (PANI)/CeO₂ composites were prepared by adding CeO₂ powder into the polymerization reaction mixture of aniline. Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD) were used to characterize the composites. Thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to study the thermal stability of the composites. IR and XRD results show that interaction exists between PANI and CeO₂. This interaction maybe is hydrogen bonding action between the hydroxyl groups on the surface of the CeO₂ and the imine groups in the PANI molecular chains. TG–DTG analysis indicates that the thermal stability of the composites is higher than that of the pure PANI. The improvement in the thermal stability of the composites is attributed to the interaction between PANI and CeO₂, which restricts the thermal motion of PANI chains and shields the degradation of PANI in the composites.     

Thermal stability of several polyaniline/rare earth oxide composites

Polyaniline/rare earth oxide composites (PANI/La₂O₃ and PANI/Sm₂O₃) were synthesized by in situ polymerization at the presence of sulfosalicylic acid (as dopant). The composites obtained were characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thermal stability of the composites was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG). The electrochemical performance of the composites was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results of FTIR, XRD, SEM, CV, and EIS show that the structure of composite has changed greatly when rare earth oxide content is >0.7 g (PANI/La₂O₃[w/w(92.7/7.3)] and PANI/Sm₂O₃[w/w(96.2/3.8)]) and the PANI in the composite has transformed into pernigraniline base (non-conducting state) from emeraldine base (conducting state). TG-DTG analysis indicates that the thermal stability of composite was higher than pure PANI, which is attributed to the interaction between PANI and rare earth oxide.     

Thermal stability and glass transition behavior of PANI/γ-Al2O3 composites

Polyaniline/γ-Al₂O₃ (PANI/γ-Al₂O₃) composites were synthesized by in-situ polymerization at the presence of HCl as dopant by adding γ-Al₂O₃ nanoparticles into aniline solution. The composites were characterized by FTIR and XRD. The thermogravimetry (TG) and modulated differential scanning calorimetry (MDSC) were used to study the thermal stability and glass transition temperature (T _g) of the composites, respectively. The results of FTIR showed that γ-Al₂O₃ nanoparticles connected with the PANI chains and affected the absorption characteristics of the composite through the interaction between PANI and nano-sized γ-Al₂O₃. And the results of XRD indicated that the peaks intensity of the PANI/γ-Al₂O₃ composite were weaker than that of the pure PANI. From TG and derivative thermogravimetry (DTG) curves, it was found that the pure PANI and the PANI/γ-Al₂O₃ composites were all one step degradation. And the PANI/γ-Al₂O₃ composites were more thermal stable than the pure PANI. The MDSC curves showed that the nano-sized γ-Al₂O₃ heightened the glass transition temperature (T _g) of PANI.     

Synthesis,Characterization and Electrorheological Properties of Polyaniline/Titanate Core-Shell Composite

In this study, a facile method was developed for the preparation of a new conducting polymer composite with core-shell structure. The surfaces of layered titanate (K₂Ti₄O₉) particles were first modified with 3-aminopropyltriethoxysilane, and then a polyaniline/titanate (PANI/K₂Ti₄O₉) composite was synthesized via chemical oxidative polymerization. The resulting composites were characterized by SEM, XRD, FTIR and TG measurements. The results indicated that the PANI deposited on the surface of K₂Ti₄O₉ particles resulted in the formation of the composite with a core-shell structure. TG analysis showed that the composite containing 28.7 wt% PANI had better thermal stability than that of pure PANI. Further, the PANI/K₂Ti₄O₉ composite particles were adopted as a dispersed phase in silicone oil for electrorheological (ER) investigation. Suspension of the composite particles exhibited typical ER behavior subjected to an external electric field under steady and dynamic oscillatory shear.     

Preparation and Characterization of In-Situ Polymerized Nanocomposites Based on Polyaniline in Presence of MWCNTs

Summary: Polyaniline (PANI) composites were prepared with both unmodified and amine modified MWCNTs with and without BaTiO₃ through in-situ oxidative polymerization. Uniform coating of PANI on the MWCNTs and BaTiO₃ surfaces was found which was evident from the Field Emission Scanning Electron Microscopic (FESEM) and High Resolution Transmission Electron Microscopic (HRTEM) images. The structure of pure and amine modified MWCNTs was identified by Fourier Transform Infrared Spectroscopy (FTIR). The thermal stability of the amine modified composite with BaTiO₃ is higher than that of the unmodified composite because of the better affinity between modified MWCNTs and polymer matrix and due to the higher stability of barium titanate itself. The capacitance of amine modified MWCNTs and BaTiO₃ composites was less than that of the pure MWCNTs composites but the thermal stability increased in amine modified MWCNTs and BaTiO₃ composites with respect to the pure MWCNTs composites. The maximum capacitance and energy density values were found in MWCNT/PANI composites which were equal to 523.20 F/g and 142.83 Wh/kg respectively at a scan rate of 10mv/s. Maximum power density was found to be 5147.70 W/kg in the same composite at a scan rate of 200 mv/s.     

Synthesis, characterization and thermal analysis of polyaniline/ZrO2 composites

Conducting polyaniline-zirconium dioxide (PANI/ZrO₂) composites were synthesized by ‘in situ’ deposition technique in the presence of hydrochloric acid (HCl) as dopant by adding the fine grade powder (average particle size of approximately 20 nm) of ZrO₂ into the polymerization reaction mixture of aniline. The composites obtained were characterized by infrared spectra (IR) and X-ray diffraction (XRD) and thermogravimetric analysis (TGA). TG curves and DTG curves of the composites suggest that the thermal degradation process of PANI/ZrO₂ composites proceeds in two-steps and the composites are more thermally stable than that of the pure PANI. The improvement in the thermal stability for the composites is attributed to the interaction between PANI and ZrO₂, which restricts the thermal motion of PANI chains and shields the degradation of PANI in the composites.     

Thermal stability of several polyaniline/rare earth oxide composites III

Polyaniline/Nd₂O₃ (PANI/Nd₂O₃) composites were synthesized by in situ polymerization at the presence of sulfosalicylic acid (as dopant). The composites obtained were characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). The thermal stability of the composites was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG). The electrochemical performance of the composites was investigated by cyclic voltammetry (CV). The results of FTIR, XRD, and CV show that the structure of composite has changed greatly when Nd₂O₃ content is ≥0.7 g and the PANI in the composite has transformed into pernigraniline base (non-conducting state) from emeraldine base (conducting state). TG–DTG analysis indicates that the thermal stability of PANI/Nd₂O₃ composites was higher than the pure PANI.     

Synthesis and characterization of conductive polyaniline/TiO2 composite nanofibers

Fibrillar conductive polyaniline/TiO₂ (PANI/TiO₂) nanocomposites with different TiO₂ amount were synthesized with a template-free in situ polymerization method and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and conductivity measurement. The morphology determination shows that the PANI/TiO₂ composite nanofibers are relatively uniform with the diameter and length in the range of 20–40 nm and 390–420 nm respectively. It also shows that the TiO₂ of the composite is rutile crystalline and PANI has some degree of crystallinity. The IR measurement indicates that there is a strong interaction between the PANI and TiO₂ nanoparticles, and it has a beneficial effect on the thermal stability of the composite nanofiber. The conductivity of PANI/TiO₂ composites changes with TiO₂ amount and reaches an optimum value of 2.86 S/cm at 11.1 wt% TiO₂. Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(4): 67–70 (in Chinese)     

Polymerization of aniline in the interlayer space of molybdenum trioxide and its electrochemical properties

Molybdenum trioxide/polyaniline (MoO₃/PANI) composite was prepared first by ion-exchange reaction between aniline (ANI) and dodecylamine (DDA) which was intercalated precursor, and then was formed under the polymerization of ANI within the interlayer space of MoO₃ at 120 °C for 3 d in air. According to powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, infrared spectroscopy and electrochemical testing, MoO₃/PANI composite has layered structure, and its interlayer spacing is 1.127 nm. Moreover, it has high thermal stability with the compound and completes its weight loss at 751.9 °C. Electrochemical investigation shows that MoO₃ is the major active substance in the MoO₃/PANI electrode, and MoO₃/PANI electrode demonstrates better conductivity and electrochemical activity than pure MoO₃ electrode, attributed to the promotion of Li⁺ and/or electron transport. In addition, the alternating current impedance proves that if the resistance of MoO₃/PANI electrode reduces apparently, the electrochemical activity will increase correspondingly, the same as the relationship between the ohmic resistance and the electrical conductivity.     

Synthesis,characterization, luminescence and magnetic properties of composite of polyaniline with nickel bisacetylacetonate complex

The present study involves the synthesis of polyaniline (PANI) and its composite with nickel bis(acetylacetonate) complex (Ni(acac)₂) via chemical oxidative polymerization method. PANI-Ni(acac)₂ composite was characterized by energy dispersive X-rays (EDX), fourier transformer infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Luminescence study was performed by UV–visible and fluorescence techniques. Relative fluorescence quantum yield of composite is a few orders of magnitude higher than pure PANI. The high fluorescence quantum yield of composite is probably due to greater chances of exciton formation and subsequent radiative decay to the ground state. Differential scanning calorimetric analysis (DSC) revealed higher thermal stability of composite than pure PANI, thereby allowing its use in devices which run at higher temperatures. On increasing the applied magnetic field, magnetic moment increases in both Ni(acac)₂ complex and PANI-Ni(acac)₂ composite, unlike to that in pure PANI. Thus, the present study holds promise for thermal purposes, luminescence properties and magnetic applications of the polyaniline composite.     

Synthesis,characterization and thermal analysis of polyaniline (PANI)/Co<Subscript>3</Subscript>O<Subscript>4</Subscript> composites

Conducting polyaniline/Cobaltosic oxide (PANI/Co₃O₄) composites were synthesized for the first time, by in situ deposition technique in the presence of hydrochloric acid (HCl) as a dopant by adding the fine grade powder (an average particle size of approximately 80 nm) of Co₃O₄ into the polymerization reaction mixture of aniline. The composites obtained were characterized by infrared spectra (IR) and X-ray diffraction (XRD). The composition and the thermal stability of the composites were investigated by TG-DTG. The results suggest that the thermal stability of the composites is higher than that of the pure PANI. The improvement in the thermal stability for the composites is attributed to the interaction between PANI and nano-Co₃O₄.     

兼具电磁性能的PANI/ZnFe2O4纳米复合材料的制备

运用改进的溶胶凝胶-原位聚合法制备出了兼具电、磁性能的PANI/ZnFe2O4纳米复合材料,借助TEM、XRD、FTIR、四探针电导率仪和VSM(振动样品磁强计)等技术研究了复合材料的结构及其电磁性能。结果表明,通过该法可以实现ZnFe2O4与PANI的有机复合,制得纳米尺寸的、ZnFe2O4与PANI相间以化学键结合的纳米复合材料;复合材料兼具电、磁性能,其导电率随ZnFe2O4含量增加而降低,饱和磁化强度随之而升高,复合物的矫顽力在所研究的含量范围内均较纯ZnFe2O4大,且随ZnFe2O4含量的增加呈先升高后降低的变化趋势。此外,对ZnFe2O4进行HNO3预处理可以有效改善复合材料的电磁性能。     

一步法合成聚苯胺/十二烷基苯磺酸钠超疏水复合材料

在阴离子表面活性剂十二烷基苯磺酸钠(SDBS)体系中,采用一步法制得聚苯胺/SDBS超疏水复合材料.利用场发射扫描电子显微镜(FESEM)观察产物形貌并测定其元素组成.通过傅里叶变换红外光谱仪、紫外-可见光谱仪、X射线衍射等对其结构进行表征,用视频接触角测量仪测定材料的亲疏水性.考察SDBS浓度和溶液酸度对产物形貌及疏水性能的影响,探讨疏水机理.结果表明:在pH=1-9,SDBS浓度大于0.016 mol?L-1条件下,所制备复合材料的水接触角大于150°,SDBS掺杂使得苯胺单体的转化率高达98%.两亲分子SDBS亲水磺酸基与聚苯胺主链上的亚胺基不仅存在静电引力,而且能形成磺酰胺键,聚苯胺主链间又以氢键相互连接,SDBS分子的疏水烃基有序排列朝向聚苯胺主链外侧,从而组装形成具有微纳结构的聚苯胺/SDBS超疏水复合材料.本文结果有利于更好地理解聚苯胺/SDBS超疏水性复合材料的形成机理,对超疏水材料的设计提供新思路.     

Study on Fe3O4/polyaniline electromagnetic composite hollow spheres prepared against sulfonated polystyrene colloid template

Fe₃O₄/polyaniline (PANI) composite hollow spheres were prepared by using sulfonated polystyrene (SPS) microspheres as templates. The sulfonic acid groups were applied to induce absorbing Fe₃O₄ nanoparticle, and subsequently, conductive PANI was grown. Finally, the polystyrene cores were selectively dissolved to yield composite hollow microspheres with electromagnetic properties. The analysis results indicated that the adsorption of Fe₃O₄ on template core by electrostatic interaction resulted in magnetic composite microspheres. The conductivity of composite hollow spheres was remarkably increased after polyvinylpyrrolidone modification which favored the growth of PANI on SPS/Fe₃O₄ and enhanced the integrity of hollow microspheres. The saturated magnetization of the composite hollow microspheres was tuned from 2.7 to 9.1 emu/g, and the conductivity was in the range from 10^?2 to 10⁰?S/cm.     

Preparation,characterization and thermal decomposition of phenylenediammonium sulfate salts Part. XVI

Polyaniline/α-Al₂O₃ (PANI/α-Al₂O₃) composites were synthesized by in situ polymerization through ammonium persulfate ((NH₄)₂S₂O₈, APS) oxidized aniline using HCl as dopant. XRD and FTIR were used to characterize the PANI/α-Al₂O₃ composites. The thermal stabilities and glass transition temperature (T _g) of PANI/α-Al₂O₃ composites were tested using thermogravimetric (TG) method and modulated differential scanning calorimetry (MDSC) technique. The results of TG showed that the thermal stability of PANI/α-Al₂O₃ composite increased and then decreased with the increase in α-Al₂O₃ content. The derivative thermogravimetry (DTG) curves showed one step degradation of PANI when the α-Al₂O₃ content was lower than 52.5 mass%, and exhibited two steps degradation when the α-Al₂O₃ content was higher than 63.6 mass%. The MDSC curves showed that the T _g of PANI/α-Al₂O₃ composites increased and then decreased with the augment of α-Al₂O₃ for the interaction between PANI chains and the surface of α-Al₂O₃.     

Preparation and characterization of polyaniline-containing Na-AlMCM-41 as composite material with semiconductor behavior

Composite material formed from a mesoporous aluminosilicate, Na-AlMCM-41, with conducting polyaniline (PANI) has been synthesized by an in situ polymerization technique. Studies of aniline adsorption over mesoporous Na-AlMCM-41 synthesized in our laboratory allowed us to find the modes in which aniline interacts with the active sites of Na-AlMCM-41. In order to obtain the best reaction conditions to polymerize aniline onto Na-AlMCM-41, aniline was first polymerized to produce pure PANI. Hence, the oxidative in situ polymerization was carried out by two procedures, differing in the polymerization time and in static or stirring conditions. Studies of infrared spectroscopy and UV-vis spectroscopy indicated that higher polymerization time and static conditions allowed us to obtain mainly polyaniline in emeraldine form on the host. The N(2) isotherm of the polyaniline/Na-AlMCM-41 composite (PANI/MCM) indicated that the shape was similar to that of MCM, but the shift to saturation transition to lower partial pressure shows that the channels are occupied by PANI and they are now narrowed. The thermal properties of PANI, Na-AlMCM-41, and composite were investigated by TGA analyses and we found that the polymer shows higher thermal stability when it is forming the composite. Scanning electron microscopy indicated that PANI is not on the outer surface of the host. Conductivity studies show that PANI/Na-AlMCM-41 exhibits semiconductor behavior at room temperature and its conductivity was 7.0 x 10(-5) S/cm, smaller than that of pure polyaniline. PANI/Na-AlMCM-41 conductivity shows an increase as temperature increases. Magnetic measurements at room temperature confirmed that the composite has paramagnetic behavior; at lower temperatures the composite became diamagnetic.     

Synthesis of stable aqueous dispersion of graphene/polyaniline composite mediated by polystyrene sulfonic acid

A facile method of producing stable aqueous dispersion of graphene/polyaniline (PANI) composite is described, which involves the in situ polymerization of aniline on the surface of graphene with the aid of polystyrene sulfonic acid (PSS). The prepared aqueous graphene/PANI composite dispersion was very stable and no aggregation or precipitation was observed for several weeks. The excellent aqueous dispersibility and stability of the graphene/PANI composite is attributed to the cooperative interactions of π stacking interaction between PSS, PANI, and the graphene basal planes, and the electrostatic repulsions between negatively charged PSS bound on graphene/PANI composite. Fourier transform‐infrared spectrometry (FTIR), ultraviolet‐visible spectra (UV–vis), and Raman spectra confirmed the interaction of PANI and graphene in the composite, which effectively delocalize the electrons. In addition, the composite showed three orders of magnitude of conductivity increase compared with pure PANI. This new approach is simple, fast, and straightforward, representing a significant improvement in the processing of graphene/PANI composites. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

PANI/Ce(OH)3-Pr2O3·3H2O/NanoG复合材料制备与表征

开发了反胶束模板-原位聚合纳米复合法制备聚苯胺(PANI)/Ce(OH)3-Pr2O3·3H2O/石墨纳米薄片(NanoG)纳米复合材料的方法.膨胀石墨在乙醇水溶液中经超声处理制得石墨纳米薄片,以苯胺的氯仿溶液为油相,稀土金属离子Pr3+、Ce3+水溶液为水相,依靠表面活性剂十六烷基三甲基溴化铵(CTAB)自组装形成的反胶束为模板-制备PANI/Ge(OH)3-Pr2O3·3H2O/NanoG复合材料.利用红外光谱(FTIR)、扫描电镜(SEM)、透射电镜(TEM)和 X-射线衍射(XRD)对该复合材料进行了表征和分析,研究了其导电性能和热性能.结果表明,PANI/Ce(OH)3-Pr2O3·3H2O/NanoG复合材料各相分散均匀,稀土纳米粒子在体系中以棒状的形态分布.热重分析表明,该复合材料的热稳定性明显提高;导电性研究说明,石墨纳米薄片的特殊的结构(较大的径厚比)对其在聚合物基体中形成导电网络具有重要作用;PANI/Pr2O3-Ce(OH)3/NanoG纳米复合材料的渗滤阀值低于1.0wt%.     

Polyanilme-montmorilltonite (PANl-MMT) nanocomposites: Mechanochemical synthesis,structure, thermostability and electrical properties

Polyaniline (PANI)-montmorillonite (MMT) nanocomposites were prepared by direct intercalation of aniline molecules into MMT galleries, followed by in situ mechanochemical polymerization under solvent free conditions. X-rays diffraction, Fourier Transform Infra Red analyses and UV-vis spectroscopy confirmed the successful synthesis of polyaniline chains between the MMT nano-interlayers. On increasing the amount of MMT basal spacing decreased gradually, suggesting less intercalation with decreasing amount of aniline. Scanning electron micrographs demonstrated strong differences between the morphologies of PANI-MMT nanocomposites and those of pure MMT and PANI. DC conductivity was measured in the temperature range from 145 K to 303 K using four probe methods. Temperature dependent DC conductivity of PANI and all the PANI-MMT composites followed 3 dimensional variable range hopping (3D VRH) model. Frequency dependent AC conductivity (σ_AC), dielectric constant (ɛ′) and loss factor (ɛ″) have been measured in the frequency range 10²–10⁶. All these measured quantities; σ_AC, ɛ′ and ɛ″ decreased with the increase in MMT content in the composites at all frequencies. The frequency dependence of σ_AC displayed a low frequency region below 10⁴ Hz with almost constant conductivity, while above this frequency a rapid rise in σ_AC was observed with a power law of frequency dependence with an exponent equal to 0.7. Both real and imaginary parts of the permittivity exhibited a low frequency dispersion which has been attributed to hopping of polarons and bipolarons in PANI and its composites. The thermal stability was checked by thermogravimetric analysis (TGA) and was found to be enhanced due to addition of MMT in the PANI.