Metanilic Acid Research Articles

Sulphated natural bio-polysaccharide grafted magnetic nanoparticles: Experimental and simulation towards safe and biocompatible polymeric membrane

Blood biocompatibility and permeability are major challenges that limit the wide implementation of polyethersulfone membranes for hemodialysis and bio-related applications. In this regard, polyethersulfone's surface modification is a commonly used strategy to improve permeability/selectivity, prevent protein-based fouling, and suppress the inflammation of the immune response. As a new approach to enhancing blood biocompatibility, this paper reports a feasible and effective method for the synthesis of heparin-like structures by modifying the polysaccharide guar gum macromolecule with magnetic nanoparticles and metanilic acid. The prepared magnetic, sulphated polysaccharide was blended with polyethersulfone to obtain a hydrophilic and biocompatible membrane surface. The modified membranes show an improved permeability of 144 L m−2 h−1 bar −1. A comprehensive and in-depth analysis of the protein adsorption on the membrane surface is also conducted. Blood compatibility tests reveal that the polyethersulfone-modified membrane demonstrates a low hemolysis rate, prolonged activated partial thromboplastin time, and low platelet adhesion. It is also performed simulation studies based on molecular docking between different guar gum-modified structures and each of human serum albumin and immunoglobulin. Accordingly, the docking results are in line with the practically obtained biocompatibility analyses. Through the obtained results, this study uniquely affirms that the modification of polyethersulfone membranes with magnetic and negatively charged guar gum has promising potential for effective usage in bio-related applications.

Development of Novel Formaldehyde-Free Melamine Resin for Retanning of Leather and Reduced Effluent Discharge in Water

The objective of this study was to develop a novel melamine-based resin suitable for producing formaldehyde-free leather with improved retanning properties. The resin was prepared by optimized condensation of melamine, glyoxal and metanilic acid. The novel resin was compared with a commercial resin against different parameters. Functional group analysis of the polymer structure and the route of synthesis was verified with the help of FT-IR spectroscopy. A Leica metallurgical microscope coupled with a CCD camera was used for SEM analysis. The results revealed that the mechanical and organoleptic properties of the novel resin were better than those of the commercial melamine resin. Tensile strength, tear strength and percentage elongation of leather were increased by 17.43%, 10.41% and 8.62%, respectively, in the direction parallel to the backbone, while the increases in these parameters were 15.17%, 9.79% and 6.0%, respectively, in the direction perpendicular to the backbone at the same dose. We observed a 100% reduction in free formaldehyde content in retanned leather as well as in effluent produced by the novel melamine resin. Pollution load study of effluent showed reductions in chemical oxygen demand, total suspended solids and total dissolved solids by 9.21%, 5.60% and 6.97%, respectively, for the novel melamine resin, reflecting its improved exhaustion. The fiber structure of the leather produced by the novel melamine resin was more orderly arranged, showing its improved retanning. These results prove that the novel melamine resin is an effective retanning agent suitable for producing formaldehyde-free leather with a reduction in effluent pollution load. This work introduces an alternative to formaldehyde for amino resins to address its carcinogenic effects.

High performance in-situ tuned self-doped polyaniline (PANI) membranes for organic solvent (nano)filtration

Cross-linked polyaniline (PANI) membranes are attractive for organic solvent nanofiltration (OSN). However, inadequate tuneability to cover the full nanofiltration (NF) separation range, prolonged post-treatment cross-linking using hazardous organic chemicals and poor permeance limit their widespread application. This work introduces a new strategy to tune the transport properties of PANI membranes to suit the rejection spectrum of NF membranes without compromising permeance. Incorporating different molecular weight organic acids, metanilic acid (MA) and poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA), facilitated cross-linking during polymer precipitation at different aqueous coagulation bath acidic strength using non-solvent induced phase separation (NIPS). Static ageing tests for PANI membranes immersed in tetrahydrofuran (THF) for 30 days showed no physical or chemical deterioration. All membranes were stable during long-term dynamic crossflow filtration tests over 250 h with sequential feed of methanol, acetonitrile and THF. THF permeance was 2.1–16.4 L m−2 h−1 bar−1 with apparent molecular weight cut off (MWCO) between 250 and 1000 g mol−1. PAMPSA doped membranes were successfully cross-linked but required wet annealing post-treatment to obtain membranes in NF range. The MA doped membranes surpassed the performance of cross-linked PANI membranes with glutaraldehyde (organic cross-linker) showing a 2.5 times higher permeance with better rejection. In comparison to commercial polyimide membranes, PANI membranes prepared in coagulation bath ≥0.5 M HCl(aq) were stable in N,N-dimethylformamide (DMF) whereas the former suffered complete damage. This work represents a simplified technique to in-situ optimise permselective properties of OSN self-doped PANI membranes for various applications in food, pharmaceutical and petrochemical industries.

Electrochemically imprinted self-doped polyaniline as highly sensitive voltammetric sensor for determination of bismuth in water, wastewater, and pharmaceutical samples

A novel electrochemically imprinted self-doped polyaniline (SDPAn) film-modified glassy carbon electrode (GCE) for bismuth ion (Bi3+) determination was prepared here based on copolymerization of polyaniline with metanilic acid, GCE/P(An-co-MA). Firstly, prepared SDPAn was characterized by using solid-state UV–visible, SEM, and EDXA techniques. Then, the GCE/P(An-co-MA) electrode was templated by several consecutive reduction/oxidation potential steps in Bi3+ solution for improving its selectivity to Bi3+ ions. Affecting parameters on detection signal like MA concentration, pH, and time in polymerization step and preconcentration potential and incubation pH in preconcentration step have been optimized by means of experimental design. The differential pulse anodic striping voltammetric signal of the GCE/P(An-co-MA) in optimized conditions was recorded and a linear relation ship from 1.0 × 10−9 to 1.0 × 10−4 M of Bi3+, R2 as 0.9960, with detection limit as 0.48 nM Bi3+, and RSD as 1.49% was obtained. This sensor was successfully applied for voltammetric determination of Bi3+ ions in water, wastewater, and pharmaceutical samples.

Developmental effects of three textile chemicals on locomotor activity, antioxidant markers and acetylcholine esterase activity in zebrafish

Textile chemicals discharged into the water bodies cause huge impact on human health and environment. However, the adverse effects of textile chemicals during critical period of brain development are not explored. This study uses zebrafish to assess the developmental toxicity of three textile chemicals. Zebrafish embryos were exposed to different concentrations (1, 5, 10, 20 and 40 PPM) of Naphthalene sulfonic acid (NSA), Metanilic acid (MA) and Acid blue 113 (AB113) from 18 h post-fertilization (HPF) to 96 HPF, respectively. Several endpoints, such as mortality, morphological abnormalities and locomotor activity of embryos and larvae were studied. Biochemical detection of oxidative stress, glutathione and acetylcholine esterase was subsequently tested. The survival rate was decreased (LC (50): 1PPM) by NSA, MSA or AB113 and at > 5PPM a 90% mortality was observed respectively. Exposure to 1 PPM of NSA, MSA or AB113 significantly reduced the locomotor activity in an age dependent manner. However, no neurodegenerative phenotypes were noted. The glutathione and acetylcholine esterase activity (P <0.05) was decreased while malondialdehyde content was accumulated by NSA, MSA or AB113 treatment. The overall findings suggest that the selected textile dyes exposed during critical window development is able to produce oxidative stress and exert noticeable effects on locomotor activity in zebrafish embryos by altering acetylcholine esterase activity.

Doping of transition metal dichalcogenides in molecularly imprinted conductive polymers for the ultrasensitive determination of 17β-estradiol in eel serum

Molecularly imprinted polymers (MIPs) have been developed to replace antibodies for the recognition of target molecules (such as antigens), and have been integrated into electrochemical sensing approaches by polymerization onto an electrode. Electrochemical sensing is inexpensive and flexible, and has demonstrated utility in point-of-care devices. In this work, several 2D (conductive) materials were employed to improve the performance of MIP sensors. Screen-printed electrodes were coated by the electropolymerization of aniline and metanilic acid, commingled with target molecules and various 2D materials. Tungsten disulfide (WS2) with an average particle size of 2 μm was found to increase the sensitivity of detection of molecularly imprinted conductive polymer-coated electrodes to 17β-estradiol. As estradiol concentrations are important to eel aquaculture, we screened eel serum samples to determine their 17β-estradiol concentrations, which were found to be in the range 28.2 ± 3.6 to 73.0 ± 11.6 pg/mL after dilution. These results were in agreement with measurements using commercial immunoanalysis.

A multichannel system integrating molecularly imprinted conductive polymers for ultrasensitive voltammetric determination of four steroid hormones in urine.

This work reports on a modularized electrochemical method for the determination of the hormones cortisol, progesterone, testosterone and 17β-estradiol in urine. These hormones were employed as templates when generating molecular imprints from aniline and metanilic acid by electropolymerization on the surface of screen-printed electrodes. The electrically conductive imprint was characterized by SEM, AFM and cyclic voltammetry. A four-channel system was then established to enable simultaneous determination of the hormones by cyclic voltammetry. The detection limits for cortisol, progesterone, testosterone and 17β-estradiol are as low as 2, 2.5, 10 and 9 ag·mL-1 (for S/N = 3). Graphical abstract A four-channel system was established to enable simultaneous determination of 4steroid hormones by cyclic voltammetry and by using moleculalry imprinted polymers.

Sulfonate···Pyridinium Supramolecular Synthon: A Robust Interaction Utilized to Design Molecular Assemblies

An approach for supramolecular design through a sulfonate··· pyridinium synthon has been adopted to achieve the structural modulations in molecular complexes of metanilic acid and various pyridyl derivatives. Layered ionic solids [(3-ABSA)2–(4,4′-BPY-H)2+(4,4′-BPY)] (1) and [(3-ABSA)−(4,4′-BPP-H)+] (2) have been obtained by reacting metanilic acid (3-ABSA-H) with linear bis-4-pyridines: 4,4′-bipyridine (4,4′-BPY) and 4,4′-trimethylenedipyridine (4,4′-BPP). 1a, a polymorph of 1, obtained with a slight excess of metanilic acid, also exhibits the layered ionic structure. The tendency of bis-4-pyridines to form infinite N+–H···N assisted chains and hence layered structures is also supported by the literature. Attempts to break down the layered structures by employing nonlinear bis-pyridines, 2,2′-bipyridine (2,2′-BPY) and 1,7-phenanthroline (1,7-phen), lead to the isolation of [(3-ABSA)−(2,2′-BPY-H)+·H2O]2 (3) and [(3-ABSA)−(1,7-Phen-H)+(1,7-Phen)·H2O] (4). Compound 3 displays two-dimensional (2-D) framework ...

Sulfonated Nonpolymeric Aminophosphonate Scale Inhibitors—Improving the Compatibility and Biodegradability

Phosphonate-based scale inhibitors are widely used in the upstream oil and gas industry, but many of them lack good compatibility with high calcium brines. Here, we report the synthesis of several nonpolymeric aminobismethylenephosphonates with an added sulfonate group to improve the compatibility. The chemicals are 2-(bis(phosphonomethyl)amino)alkane-1-sulfonic acid (alkane = methane, ethane, and propane labeled SI-1 to SI-3, respectively), N,N-bis(phosphonomethyl)cysteic acid (SI-4), and N,N-bis(phosphonomethyl) metanilic acid (SI-5). To screen their performance, we carried out dynamic scale loop inhibition performance tests for calcium carbonate and barium sulfate, thermal stability tests, and calcium compatibility tests up to 10 000 ppm calcium ions and compared them to some well-known oilfield scale inhibitors. Seawater biodegradation over 28 days (BOD28) was also investigated by the OECD 306 method. All new inhibitors demonstrated good calcite inhibition properties, but only SI-1 and SI-2 gave fairly good barite inhibition. SI-2 stood out as an excellent calcite inhibitor, suitable for use in very high calcium-containing brines. SI-2 could also provide protection against barite deposition under mild to medium scaling potentials and gave a reasonable rate of biodegradation (BOD28 = 46%). SI-1 and SI-4 gave BOD28 values of 79 and 84%, respectively, and can be classed as “readily biodegradable”. Of the two products, SI-1 seems the most promising for further studies given the better calcite and barite scale inhibition properties. Of the SIs tested, SI-5 showed the best thermal stability at 130 °C and could therefore be a useful downhole squeeze SI for fairly high-temperature wells. Its BOD28 value was 41%. Overall, the study highlights the difficulty of designing a scale inhibitor with all of the major features required for application over a wide range of field conditions.

Acidic Derivatives of Melamine as Template in Copolymerization of Aniline and Metanilic Acid

ABSTRACTIn this paper, new polymer composites were synthesized by template copolymerization of aniline and metanilic acid in the presence of prepared melamine triacetic acid and poly(melamine-co-citric acid) as polyacids and dopants. The properties of the poly(aniline-co-metanilic acid) composites were studied by Fourier transform infrared, X-ray diffraction, scanning electron microscope, CV, and differential scanning calorimeter analysis. The four-point probe technique was used for evaluating the electrical conductivity of the composites. The scanning electron micrographs disclosed that the products had the morphology with agglomerated distorted spherical shapes with the average size of 40–50 nm. Also, the solubility of the composites had been improved notably in organic solvents.

Cytotoxicity of Metanilic Acid and its Degradation Products

Moraxella osloensis, a bacterium with dye degrading ability was screened for its ability to degrade metanilic acid, an intermediate in the synthesis and a biodegradation product of azo dyes. The organism was capable of removing 72% of 20 mg l-1 of metanilic acid. Cytotoxicity studies using HCT15, Hep2 and 3T3 cell lines clearly indicated the toxicity of the metanilic acid. The culture filtrate containing the degradation product of metanilic acid after degradation by Moraxella osloensis was found to be comparatively less toxic indicating that the metanilic acid has undergone structural and chemical changes during biodegradtion. The cancer cell lines were found to be more resistant to metanilic acid and their degradation products than their normal counterparts.

Preparation and dedoping-resistant effect of self-doped polyaniline/cellulose fibers (SPANI/CF) hybrid

Self-doped polyaniline/cellulose fibers (SPANI/CF) hybrid was in situ prepared by copolymerization of aniline and metanilic acid in presence of cellulose fibers to improve its dedoping-resistant ability. The results indicated that the SPANI/CF hybrid was remarkably more resistant to dedoping by alkaline aqueous solution than the polyaniline/cellulose fibers (PANI/CF) hybrid. Self-doping did not increase the electrical conductivity of the hybrid, but increased its flame retardancy. Both the electrical conductivity and oxygen index of the SPANI/CF hybrid decreased after ammonia soaking treatment, and the color changed gradually from green to bluish violet with increase of the ammonia concentration. The original (non-dedoped) and dedoped SPANI/CF and PANI/CF hybrids were characterized by attenuated total reflection (ATR) Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) analyses, revealing the occurrence of deprotonation during ammonia soaking treatment. Compared with the PANI/CF hybrid, additional ring substitution with sulfo groups was probably responsible for the significantly better dedoping-resistant ability of the SPANI/CF hybrid.

Electrodeposition of self-doped copolymers of aniline with aminobenzensulfonic acids on stainless steel. Morphological and electrochemical characterization

Self-doped conducting polyaniline (PAn) films were deposited on passive stainless steel (SS) AISI304 substrates by cyclic potential sweep deposition from aqueous mixed monomer solutions of aniline (An) and different aminobenzenesulfonic acids (2-, 3- or, 4-aminobenzenesulfonic acid, ABSA), without the presence of a supporting electrolyte. Two different An concentrations were examined (0.01 and 0.05 M), while the concentration of each ABSA used was kept constant at 0.1 M. The surface morphology and roughness of the produced stable conducting copolymer thin films was studied by atomic force microscopy (AFM) and their electrochemical behavior by cyclic voltammetry. The decrease of An concentration enhanced the electropolymerization in the case of 2- and 3-ABSA, namely, orthanilic (OA) and metanilic (MA) acids, respectively, while a deceleration was observed for 4-ABSA (sulfanilic acid, SA). The shapes and sizes of the obtained morphological features depended on the ABSA reactivity and An concentration. AFM data indicated the formation of globular micro/nanostructures for all the examined copolymers, P(An-co-ABSA). Tubular micro/nanostructures, which were more desirable due to their promising practical applications, were apparent only in case of OA and SA and in larger numbers at the lower An concentration of 0.01 M. As ABSA had the function of the comonomer, surfactant, and internal dopant, it is suggested that the tubular micro/nanostructures were rather related to an interfacial self-assembly of sulfonated PAn oligomers at the early stage of the copolymerization process. Cyclic voltammetry indicated that redox processes of the SS|P(An-co-ABSA) electrodes in acid solutions are characteristic of a partially sulfonated PAn. The electrochemical activity of the SS|P(An-co-ABSA) electrodes is also kept in neutral media. Open circuit potential measurements and electrochemical impedance spectroscopy show that the SS|P(An-co-ABSA) electrodes are stable in acid media. Electronic and steric effects control the fraction of ABSA and its distribution in the copolymer chain resulting in differences in the redox potential and charge storage in the three copolymers.

Nanostructured poly(aniline-co-metanilic acid) as platinum catalyst support for electro-oxidation of methanol

Nanostructured poly(aniline-co-metanilic acid) is prepared using the chemical oxidative polymerization of aniline (Ani) and metanilic acid (Maa). The copolymerization of poly(aniline-co-metanilic acid) with various molar feed ratios of Ani/Maa is conducted to attain highly porous nanowire copolyanilines. The as-prepared copolyanilines are characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The XPS results indicate that a saturated doping state is achieved when the Ani/Maa ratio is less than 20/1. The SEM images reveal that these films are composed of highly porous nanowires when the feed molar ratio of Ani/Maa is more than 4/1. The copolyanilines are used as Pt catalyst supports. Transmission electron microscopy (TEM) results indicate that Pt particles disperse more uniformly onto the highly porous nanowires of P(A10-M) (feed molar ratio = 10:1) than onto other copolyanilines, and that the P(A10-M)-Pt electrode has the highest active surface area. Cyclic voltammetry results and chronoamperometric response measurements show that the P(A10-M)-Pt electrode has the highest electrocatalytic activity and the best long-time stability toward methanol oxidation among polyaniline-Pt and copolyaniline-Pt electrodes.

Detection of dopamine on a poly(metanilic acid) decorated two-dimensional gold cavity array electrode

A shape-controllable, highly ordered, two-dimensional gold cavity array (GCA) electrode was prepared by electrodeposition using a closely packed monolayer of 1.2 μm-diameter polystyrene spheres as a template and was characterized by FESEM and XRD. A significant enhancement for the electrooxidation of dopamine at this nanostructured electrode was found due to the increased amount of the active surface area. By electropolymerizing a poly(metanilic acid) thin film on its surface, the enhanced electrochemical properties of the GCA electrode were maintained, and the antifouling property was improved. The SWV technique was used for the trace determination of DA, and the dependence of current vs. concentration was linear from 0.2 to 100 μM with a regression coefficient of 0.9988, and the detection limit of DA was ∼0.08 μM. Furthermore, the signals of DA and UA can be well distinguished at this poly(metanilic acid) modified GCA electrode. The proposed method was applied to the selective and precise analysis of DA in commercial injections.

Anti-corrosion performance of nanostructured poly(aniline-co-metanilic acid) on carbon steel

In order to investigate the effect of a strongly hydrophilic substituent group on the anticorrosion properties of polyaniline (PANI) coatings, sulfonic acid groups (SO3H) were introduced into the polyaniline molecular structure by the copolymerization of aniline (ANI) and 3-aminobenzenesulfonic acid (metanilic acid, MA), using ammonium persulfate as an oxidant. The MA/ANI monomer ratio of the poly(aniline-co-metanilic acid) (PANIMA) products was systematically varied in the range 0–1. The PANIMA copolymers contained sulfur in the following forms: HSO4− from the external dopant (H2SO4 obtained from the reduction of the persulfate oxidant) or SO3H groups from the external MA dopant, and SO3H groups from the metanilic copolymerization unit. The influence of HSO4− or SO3H in the external dopant and SO3H in the copolymerization unit on the anticorrosive properties of PANIMA was observed. The morphologies of the different PANIMA products were characterized by SEM. At low MA/ANI ratios, PANIMA nanofibres formed whereas at near stoichiometric MA/ANI ratios PANIMA nanogranules were obtained. The chemical structure of the PANIMA products was determined by FTIR, UV–vis spectroscopy and XRD. The anti-corrosion behavior of PANIMA coated carbon steel electrodes was investigated in 1M H2SO4 solutions by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). Results show that the PANIMA coatings offer good anti-corrosion protection to carbon steel in 1M H2SO4 solutions, with the degree of protection depending on the sulfonic acid group and HSO4− dopant content in the coatings. Low sulfur content in the PANIMA coatings afforded the best protection, though the performance of all PANIMA coatings was inferior to PANI itself under the applied testing conditions.

In situ STM and ex situ XPS examination of the adsorption and polymerization of metanilic acid and aniline on Au(1 1 1) electrode

Oxidation of aniline and its derivatives can yield cationic radicals, which induce chain reactions to produce polymeric materials with notable conductivity. When these events occur on ordered electrode surface, admolecules can be adsorbed in some specific manner that guides reactions to proceed in some specific directions to yield products with well-defined conformations. This study employed cyclic voltammetry, X-ray photoemission spectroscopy (XPS), and in situ scanning tunneling microscopy (STM) to study the adsorption and polymerization of metanilic acid (MA) in 0.5MH2SO4. MA molecules were adsorbed in highly ordered adlattices characterized as Au(111) – (19×31) and (27×31) at 0.5 and 0.8V (vs. reversible hydrogen electrode). These adlattices were displaced by bisulfate anions at E>1.0V. MA molecules still could be oxidized to yield polymer molecules, which lacked a well-defined structure. By contrast, MA and aniline molecules could be coadsorbed in a highly ordered Au(111) – (4×23) structure at 0.8V in 0.5M H2SO4+30mM aniline+3mM MA, which led to anisotropic oxidative polymerization in the 〈121〉 directions of the Au(111) electrode surface. According to ex situ XPS results, the as-produced linear polymeric chains were mainly polyaniline (PAN), rather than copolymer of aniline and MA. The surface structure and polymerization of aniline and MA varied greatly with their molar ratios. No ordered adlayer was observed in solution containing equal amounts (30mM) of MA and aniline.

Simultaneous dyeing and antibacterial finishing for cotton cellulose using a new reactive dye

Simultaneous dyeing and antibacterial finishing for cotton fabric using a new antibacterial reactive dye having a modified chemical structure to the commercial reactive dye CI Reactive Red 198 were studied. This modification was carried out by replacing metanilic acid in the commercial dye with 4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide (sulfadimidine). Optimum exhaustion and fixation values were achieved at 60g/l sodium sulphate and 20g/l sodium carbonate for both dyes. The modified dye exhibited higher substantivity, exhaustion and fixation efficiency compared to the commercial dye. Antibacterial activities of the dyed samples at different concentrations of both dyes were studied against gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria. The cotton dyed with the modified dye shows higher antibacterial efficacy compared to the dyed cotton fabric using the commercial dye, especially on gram negative (E. coli) bacteria. All the reactive dyeings also exhibited high fastness properties.

Biodegradation of Acid Blue 113 Containing Textile Effluent by Constructed Aerobic Bacterial Consortia: Optimization and Mechanism

A bacterial consortium was constructed using five different bacterial strains isolated from the effluent with the ability to degrade Acid Blue 113, a diazo dye. These organisms were identified as Citrobacter freundii (2 strains), Moraxella osloensis, Pseudomonas aeruginosa using 16S rRNA analysis and Pseudomonas aeruginosa CLRI BL22. The consortium was found to degrade 90% of the dye by 22 h in 80% diluted textile effluent supplemented with glucose and ammonium nitrate. Optimization studies using Response Surface Methodology have confirmed that the degradation process was predominantly influenced by agitation and pH where as glucose was found to have negative effect. TLC analyses indicated the presence of metanilic acid and peri acid in 24 h sample which disappeared by 48 h. The GC-MS analysis has confirmed the presence of methyl salicylic acid, catechol and β-ketoadipic acid with the RT values of 7.71, 10.88 and 15.04 respectively confirming the complete degradation of Acid Blue 113.

Self-doped polyaniline on functionalized carbon cloth as electroactive materials for supercapacitor

Carbon cloth was functionalized through cyclic voltammetric scans in 2M H2SO4 to afford functionalized carbon cloth (FC). The FC was characterized by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Self-doped polyaniline (SPAN) was deposited on FC through electro-co-polymerization of aniline and metanilic acid to get SPAN/FC which showed a specific capacitance of 408Fg−1 in 0.5M Na2SO4, based on a constant charge–discharge experiment at a current density of 1Ag−1. A symmetric model capacitor, SPAN/FC-SPAN/FC was assembled by using SPAN/FC as both of the electrodes and 0.5M Na2SO4 as the electrolyte. The charge storage property and charge–discharge cycling stability of SPAN/FC-SPAN/FC were investigated by galvanostatic experiment.