Polyaniline/single-wall carbon nanotube (PANI/SWCNT) composites for high performance supercapacitors

PANI/SWCNT composites were prepared by electrochemical polymerisation of polyaniline onto SWCNTs and their capacitive performance was evaluated by means of cyclic voltammetry and charge-discharge cycling in 1 M H₂SO₄ electrolyte. The PANI/SWCNT composites single electrode showed much higher specific capacitance, specific energy and specific power than pure PANI and SWCNTs. The highest specific capacitance, specific power and specific energy values of 485 F/g, 228 W h/kg and 2250 W/kg were observed for 73 wt.% PANI deposited onto SWCNTs. PANI/SWCNT composites also showed long cyclic stability. Based upon the variations in the surface morphologies and specific capacitance of the composite, a mechanism is proposed to explain enhancement in the capacitive characteristics. The PANI/SWCNT composites have demonstrated the potential as excellent electrode materials for application in high performance supercapacitors.     

聚苯胺/氧化石墨烯接枝复合材料的制备及电容性能研究

利用化学氧化法原位聚合制备了聚苯胺(PANI)/氧化石墨烯(GO)接枝复合材料。透射电子显微镜表明,PANI纳米颗粒均匀地分布在GO的表面;通过UV-vis光谱证实了GO和PANI之间存在着强烈的相互作用;充放电测试表明,PANI/GO纳米复合材料具有良好的电荷储存特性,最高比电容可达575 F/g。由于与GO之间的化学结合作用,PANI的充放电循环稳定性得到明显提高。     

The synthesis of covalent bonded single‐walled carbon nanotube/polyvinylimidazole composites by in situ polymerization and their physical characterization

Single‐walled carbon nanotube (SWCNT) polyvinylimidazole (PVI) composites have been prepared by in situ emulsion polymerization. Dispersion of raw SWCNTs in the PVI matrix was improved by surface modification of the SWCNTs using nitric acid treatment and air oxidation. The carbonyl‐terminated SWCNTs were covalently bonded to PVI by in situ polymerization and the SWCNT/PVI composite was thus obtained. The morphological and structural characterizations of the surface‐functionalized SWCNTs and SWCNT/PVI composites were carried out by Fourier transform infrared spectroscopy, X‐ray diffraction, conductivity measurements, scanning, and transmission electron microscopy. Thermograms of the materials were determined by the differential scanning calorimetry technique. The characterization results indicate that PVI was covalently bonded to SWCNTs and a new material was then obtained. The functionalized SWCNTs showed homogenous dispersion in the composites, whereas purified SWCNT resulted in poor dispersion and nanotube agglomeration. SWCNT/PVI composites exhibited chemical stability enhancement in many common solvents. I–V curves of the samples exhibit an ohmic character. Conductivity values for pure SWCNTs, pure PVI and SWCNT/PVI composite were measured to be 3.47, 2.11 × 10⁻⁹, and 2.3 × 10⁻³ S/m, respectively. Because of resonance, a large dielectric constant is obtained for SWCNT/PVI composite, which is not observed for ordinary materials. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Electrical conductivity and tensile properties of block‐copolymer‐wrapped single‐walled carbon nanotube/poly(methyl methacrylate) composites

Poly(methyl methacrylate) (PMMA) composites containing raw or purified single‐walled carbon nanotubes (SWCNTs) are prepared by in situ polymerization and solution processing. The SWCNTs are purified by centrifugation in a Pluronic surfactant, which consists of polyethyleneoxide and polypropyleneoxide blocks. Both the effects of SWCNT purity and non‐covalent functionalization with Pluronic are evaluated. Electrical conductivity of PMMA increases by 7 orders of magnitude upon the integration of raw or purified SWCNTs. The best electrical properties are measured for composites made of purified SWCNTs and prepared by in situ polymerization. Strains at fracture of the SWCNT/PMMA composites are nearly identical to those of the neat matrix. A certain decrease in the work to fracture is measured, particularly for composites containing purified SWCNTs (?31.6%). Fractography and Raman maps indicate that SWCNT dispersion in the PMMA matrix improves upon the direct addition of Pluronic, while dispersion becomes more difficult in the case of purified SWCNTs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41547.     

聚苯胺/SnO2复合材料的制备及其光催化应用

用光化学合成SnO<,2>为主要原料,在酸性苯胺溶液中,通过苯胺在SnO<,2>粒子表面原位聚合,制备了聚苯胺/SnO<,2>复合材料.用XRD、SEM和紫外-可见漫反射(UV-Vis)等对复合材料进行了表征.以甲基橙为目标污染物,考察了聚苯胺/SnO<,2>复合材料光催化障解污染物的性能.结果表明,含适量聚苯胺(PA...     

Doped polyaniline/multiwalled carbon nanotube composites: Preparation and characterization

Polyaniline (PANI)/multiwalled carbon nanotube (MWNT) composites with a uniform tubular structure were prepared from in situ polymerization by dissolving amino‐functionalized MWNT (a‐MWNT) in aniline monomer. For this the oxidized multiwalled nanotube was functionalized with ethylenediamine, which provided ethylenediamine functional group on the MWNT surface confirmed by Fourier‐transform infrared spectra (FT‐IR). The a‐MWNT was dissolved in aniline monomer, and the in situ polymerization of aniline in the presence of these well dispersed nanotubes yielded a novel tubular composite of carbon nanotube having an ordered uniform encapsulation of doped polyaniline. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that the nanotubes were coated with a PANI layer. The thermal stability and electrical conductivity of the PANI /MWNTs composites were characterized by thermogravimetric analysis (TGA) and conventional four‐probe method respectively. Compared with pure PANI, the electrical conductivity and the decomposition temperature of the MWNTs/PANI composites increased with the enhancement of MWNT content in PANI matrix. POLYM. COMPOS., 34:1119–1125, 2013. © 2013 Society of Plastics Engineers     

Synthesis of high conductivity Polyaniline/Ag/graphite nanosheet composites via ultrasonic technique

A new process for the synthesis of high conductivity polyaniline/Ag/graphite nanosheet (PANI/Ag/NanoG) composites was developed. Graphite nanosheet was prepared by treating the expanded graphite in aqueous alcohol solution using sonication, and a uniform silver film about 470 nm thick was obtained on graphite nanosheet surface via an improved electroless plating method. Then PANI/Ag/NanoG composites were fabricated via in situ polymerization of aniline monomer in the presence of silver coated graphite nanosheet through using ultrasonic technique. The sliver particles and composites were evidenced by scanning and transmission electron microscopy examinations, the results showed that the silver coated graphite nanosheet particles played an important role in forming conducting bridge in polyaniline matrix. According to the electrically test, the conductivity of the PANI/Ag/NanoG composites was dramatically increased compared with pure PANI. From the thermogravimetric analysis, the PANI/Ag/NanoG composites exhibited a beneficial effect on the thermal stability of pure PANI.     

Conductivity and anticorrosion performance of polyaniline/zinc composites: Investigation of zinc particle size and distribution effect

Polyaniline/zinc composites and nanocomposites were prepared using solution mixing method. Zinc (Zn) particles with an average particle size of 60 μm and zinc nanoparticles with an average particle size of 35 nm were used as fillers in polyaniline (PANI) matrix. Films and coatings of PANI/Zn composites and nanocomposites were prepared by the solution casting method. Electrical conductivity and anticorrosion properties of PANI/Zn composite and nanocomposite films and coatings with different zinc loadings were evaluated. According to the results, electrical conductivity and anticorrosion performances of both PANI/Zn composites and nanocomposites were increased by increasing the zinc loading. Also results showed that the PANI/Zn nanocomposite films and coatings have better electrical conductivity and corrosion protection effect on iron coupons compared to that of PANI/Zn composite.     

A novel soluble PANI/TPU composite doped with inorganic and organic compound acid

A series of novel soluble and thermoplastic polyurethane/polyaniline (TPU/PANI) composites doped with a compound acid, which was composed of an organic acid (p‐toluene sulfonic acid) and an inorganic acid (phosphoric acid), were successfully prepared by in situ polymerization. The effect of aniline (ANI) content, ratio of organic acid/inorganic acid, and different preparation methods on the conductivity of the TPU/PANI composites were investigated by using conductivity measurement. Lithium bisoxalato borate (LiBOB) was added to the prepared in situ TPU/PANI to coordinate with the ether oxygen groups originating from the soft molecular chains of TPU, and thus the conductivity of the composites was further enhanced. The molecular structure, thermal properties, and morphology of the TPU/PANI composites were studied by UV–visible spectroscopy, differential scanning calorimetry, and scanning electron microscopy, respectively. The results show that the in situ TPU/PANI composites doped with the compound acid can be easily dissolved in normal solvents such as dimethylformamide (DMF) and 1,4‐dioxane. The conductivity of the TPU/PANI composites increases with the increase of the ANI content, in the ANI content range of 0–20 wt %; however, the conductivity of the composites reduces with further increment of ANI content. The conductivity of the TPU/PANI composites prepared by in situ polymerization is about two orders of magnitude higher than that prepared by solution blending method. LiBOB can endow the in situ TPU/PANI composites with an ionic conductivity. The dependence of the conductivity on temperature is in good accordance with the Arrhenius equation in the temperature range of 20–80°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

PANI–LDPE composites: Effect of blending conditions

A composite based on polyaniline (PANI) and low density polyethylene (LDPE) with electrical conductivity was developed. Polyaniline was polymerized by chemical oxidation and doped with dodecyl‐benzene‐sulfonic acid (DBSA). PANI–LDPE composites were prepared via melt blending and the films were obtained by compression molding. The influence of three variables of the blending (temperature, [PANI], rotor speed) on conductivity, microstructure and mechanical properties of the composites was studied by means of statistical tools and a 2³ experimental design. The results show that the PANI concentration is the most influential variable, which mainly affects the conductivity and the elongation at break of the composites. These changes are related to the microstructure of the composites. Statistically, the other variables don't show significant influence on conductivity and mechanical properties in the studied range. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers.     

Electrochemical synthesis and optical properties of helical polyaniline nanofibers

Helical polyaniline (PANI) nanofibers were facilely synthesized via a direct electrochemical method without using any template in the presence of (1S)-(+)-camphor-10-sulfonic acid (d-CSA) or (1R)-(−)-camphor-10-sulfonic acid (l-CSA) as the dopant. The helical morphologies of the PANI nanofibers prepared from potentiostatic deposition were confirmed with SEM and TEM. The helical PANI nanofibers induced by d-CSA and l-CSA exhibited mirror-imaged circular dichroism spectra in the UV-vis range, indicating the stereochemical selectivity of the electrochemical polymerization. The colors and optical activities of these nanofibers can be maintained on an indium-tin oxide (ITO) coated electrode with a dedoping/redoping treatment. The optical activities of the helical PANI nanofibers reversibly varied with different oxidized forms, which were easily controlled by the different potentials applied to the nanofibers.     

Characterization and DC electrical conductivity of the composite films containing polyaniline‐carboxymethyl cellulose

New polymer composites containing polyaniline‐carboxymethyl cellulose (PANI‐CMC) were prepared via the polymerization of aniline hydrochloride using different concentration (wt%) of sodium CMC using ammonium persulfate as an oxidant. The thermal stability and embedded crystallinity of the composites were investigated using thermogravimetric and X‐ray diffraction analysis method, respectively. The electrical properties of the composites were examined using temperature‐dependent DC conductivity within 300–500 K. As compared to pure polyaniline the composites with increasing CMC in the PANI‐CMC composites shows the enhancement in the higher crystallinity and thermal stability, and higher electrical conductivities under equivalent conditions. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Enhanced figure of merit of poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) and SWCNT thermoelectric composites by doping with FeCl3

Poly(9,9-di-n-octylfluorene-alt-benzothiadiazole (F8BT) generally has a large Seebeck coefficient, and single-walled carbon nanotubes (SWCNTs) have high electrical conductivity. In this work, we prepared F8BT/SWCNT composites to combine the good Seebeck coefficient of the polymer and the excellent electrical conductivity of SWCNTs to achieve enhanced thermoelectric properties. For the composite materials, the maximum power factor of 1 μW mK⁻² was achieved when the SWCNT content was 60%, with the maximum ZT value of 4.6 × 10⁻⁴. After ferric chloride was employed as the oxidative dopant for the composites, the electrical conductivity of the composites improved significantly. The maximum value of power factor (1.7 μW mK⁻²) was achieved when the SWCNT content was 60%, and the ZT value of 7.1 × 10⁻⁴ was about 1.5 times as high as that of the composites with undoped F8BT. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47011.     

High electrical anisotropy in hydrochloric acid doped polyaniline/phyllosilicate nanocomposites: Effect of phyllosilicate matrix,synthesis pathway and pressure

Pressed tablets from polyaniline/phyllosilicate nanocomposites have been prepared under various conditions in order to optimize anisotropic conductivity of composite by ordering of flat phyllosilicate particles intercalated with polyaniline (PANI). Powder samples of PANI/phyllosilicate nanocomposites have been prepared using two phyllosilicates, montmorillonite and vermiculite, with a different layer charge. Two precursors were used, anilinium hydrochloride and anilinium sulfate. Prepared PANI/phyllosilicate composites were subsequently doped by hydrochloric acid via rinsing after polymerization process and for the DC conductivity measurements pressed into tablets. Applied pressure was 28 MPa and 128 MPa. Highly anisotropic conductivity has been achieved in pressed tablets. The in-plane conductivity for PANI/montmorillonite was 0.084 S/cm, i.e., 1000 × higher than in the direction perpendicular to the tablet plane. Increase of pressure up to 128 MPa led to dramatic decrease of conductivity.     

反应条件对原位聚合法制备PANI/CIP复合材料的影响

采用原位聚合法制备了核壳结构的聚苯胺(PANI)/羰基铁粉(CIP)复合材料,考察了掺杂酸种类、盐酸浓度、CIP用量、预搅拌时间等反应条件对反应过程及复合材料形貌和电导率的影响.以盐酸和对甲基苯磺酸为掺杂酸,均可得到核壳结构的PANI/CIP复合材料,但掺杂盐酸时综合效果较好.盐酸浓度为0.15 mol/L时制备PAN...     

Cellular structures of carbon nanotubes in a polymer matrix improve properties relative to composites with dispersed nanotubes

A new processing method has been developed to combine a polymer and single wall carbon nanotubes (SWCNTs) to form electrically conductive composites with desirable rheological and mechanical properties. The process involves coating polystyrene (PS) pellets with SWCNTs and then hot pressing to make a contiguous, cellular SWCNT structure. By this method, the electrical percolation threshold decreases and the electrical conductivity increases significantly as compared to composites with well-dispersed SWCNTs. For example, a SWCNT/PS composite with 0.5 wt% nanotubes made by this coated particle process (CPP) has an electrical conductivity of ∼3 × 10⁻⁴ S/cm, while a well-dispersed composite made by a coagulation method with the same SWCNT amount has an electrical conductivity of only ∼10⁻⁸ S/cm. The rheological properties of the composite with a macroscopic cellular SWCNT structure are comparable to PS, while the well-dispersed composite exhibits a solid-like behavior, indicating that the composites made by this new CPP are more processable. In addition, the mechanical properties of the CPP-made composite decrease only slightly, as compared with PS. Relative to the common approach of seeking better dispersion, this new fabrication method provides an important alternative means to higher electrical conductivity in SWCNT/polymer composites. Our straightforward particle coating and pressing method avoids organic solvents and is suitable for large-scale, inexpensive processing using a wide variety of polymers and nanoparticles.     

Single-walled carbon nanotubes and their composites with polyaniline. Structure, catalytic and capacitive properties as applied to fuel cells and supercapacitors

The structure and hydrophilic–hydrophobic properties of SWCNTs before and after oxidative functionalization were studied by standard porosimetry method. The correlation between the values of specific surface of hydrophilic and hydrophobic pores for the two types of SWCNTs is discussed. The capacity properties of SWCNTs and their composites with polyaniline were also investigated. The composite layer is shown to have exceptionally high capacitance that is due to the large surface area of the former, as well as to the proceeding of the reversible faradaic reaction of counter ions intercalation into PANI. The structure and electrocatalytic properties of platinum metals incorporated by various methods into support of SWCNTs and their composites with PANI were studied. Kinetics of the reactions proceeding in DMFC and the mechanism of catalytic influence of the support are discussed. The structure of the catalytic layer is shown to be the main factor that determines the overall catalytic activity.     

Mechanical properties of surface-functionalized SWCNT/epoxy composites

Well-dispersed epoxy/single-walled carbon nanotube (epoxy/SWCNT) composites were prepared by oxidization and functionalization of the SWCNT surfaces using polyamidoamine generation-0 (PAMAM-0) dendrimer. For comparison purposes, neat epoxy, epoxy/PAMAM-0 and epoxy/pristine-SWCNTs were also prepared. The morphology and mechanical properties of the above composite systems were investigated and correlated with the surface characteristics of SWCNTs. It is found that surface functionalization can effectively improve the dispersion and adhesion of SWCNTs in epoxy. This leads to enhancement in mechanical properties of epoxy, but the improvement is not as significant as expected. It is also found that surface functionalization agent will have an undesirable effect on the physical and mechanical properties of epoxy/SWCNT composites. Issues regarding optimization of mechanical properties of epoxy/SWCNT composites are discussed.     

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     

Preparation,characterization and electromagnetic properties of polyaniline/carbon nanotubes/nickel ferrite nanocomposites

New electromagnetic nanocomposites were prepared from polyaniline (PANI)/oxidized single‐walled carbon nanotubes (OxSWCNTs)/NiFe₂O₄ by in situ polymerization of aniline using hexanoic acid as a soft template. OxSWCNT and NiFe₂O₄ were prepared first so as to be used in the formulation of PANI composites. Transmission electron microscope (TEM) results revealed the formation of PANI nanoparticles of 60 nm diameter, OxSWCNT of 24 nm, and NiFe₂O₄ of 54 nm. Also, TEM image of the ternary composite indicated agglomerative coating of PANI appearing as a gray shells and black core of NiFe₂O₄ with widening the diameter of OxSWCNT to be around 66 nm. Dc conductivity was measured as a function of temperature. Magnetic susceptibility was measured as a function of temperature and magnetic field intensity. All samples revealed NiFe₂O₄‐dependent ferromagnetism. The activation energies for dc conductivity suggest that the conductivity is owing to hopping conduction mechanism. A synergistic effect between NiFe₂O₄ and PANI/OxSWCNT is observed. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers