Polyaniline Salt Research Articles

Formation of bacterial and fungal biofilm on conducting polyaniline

Polyaniline is an important conducting polymer with numerous applications and its surface properties, and consequently functionality, can be significantly influenced by bacterial biofilm. This paper represents the first ever study of biofilm formation on surface of polyaniline salt, polyaniline base and polyaniline doped with biologically active poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) and phosphotungstic acid. The surface energy and conductivity of the films were measured and correlated to capability of selected strains of biofilm-positive bacteria and filamentous fungi to form a biofilm thereon. It was observed that polyaniline salt did not inhibit the growth of microorganisms, whereas polyaniline doped with PAMPSA exhibited a notable effect against growth of biofilm for all the bacterial strains used. The results advance present knowledge of biofilm formation on polyaniline.

High-frequency dielectric response of polyaniline pellets as nanocomposites of metallic emeraldine salt and dielectric base

Conducting polyaniline (PANI) salt and dielectric PANI base pellets were studied in the infrared (IR) and terahertz (THz) range at room temperature and compared with the IR transmission spectra of powdered samples dispersed in potassium bromide and with those of thin films. The IR reflectivity combined with THz transmission was fitted to calculate the permittivity and IR conductivity spectra. In addition to vibration modes and Drude contribution of the free carriers in the conducting PANI, strong and broad mid-IR absorption was detected and assigned to localized carriers. Additional absorption in the far IR, much stronger in case of the conducting PANI, was assigned to Boson peak. Good agreement between the IR conductivity peaks and those from the absorbance evaluated from the transmission measurements was obtained and differences between the spectra of PANI salt and base are discussed. The dielectric and conductivity spectra of PANI salt were modeled as the spectra of a composite of PANI base and metallic PANI reported by Lee et al., Nature 441, 65 (2006). Effective medium approach using three different models was applied and discussed. The best results, including the semiconductor-like temperature dependence of the low-frequency conductivity, were obtained with the generalized Lichtenecker model. The strong permittivity increase on decreasing frequency below the THz range is discussed and compared with the literature data.

Simultaneous Oxidation and Doping of Aniline to Polyaniline by Oxidative Template: Electrochemical Performance in Supercapacitor

Polyaniline salts containing sulfuric acid and cetyltrimethylammonium sulfate dopants were prepared by aqueous (PANI-Aq), emulsion (PANI-Em), and interfacial (PANI-In) polymerization pathways using cetyltrimethylammonium peroxodisulfate as an oxidative template. Formation of polyaniline was confirmed from infrared and X-ray diffraction spectral results. Value of conductivity (15 S cm−1) of the polyaniline salt prepared by emulsion polymerization pathway was higher with that of the conventional polyaniline salt. PANI-Aq, PANI-Em, and PANI-In showed layered, flower petals, and nanorod and flower petals morphologies, respectively. These polyaniline salts were used as electrode in supercapacitor. Specific capacitance of PANI-Em, PANI-Aq, and PANI-In were 520, 484, and 474 F g−1, which were higher than the conventional PANI-H2SO4 salt (390). Energy density was 26, 24.2, and 23.6 Wh kg−1, respectively at a power density of 120 W kg−1. After 3000 charge-discharge cycles, retention in the specific capacitance values of polyaniline salts was 86% (PANI-Em), 85.4% (PANI-Aq) and 76.1% (PANI-In).

Role of dual dopants in highly ordered crystalline polyaniline nanospheres: Electrode materials in supercapacitors

ABSTRACTAniline is oxidized by ammonium persulfate oxidant with a weak organic acid, 1,3‐(6,7)‐napthalene trisulfonic acid (NTSA), via an aqueous polymerization pathway to polyaniline (PANI) salt. The effects of the sodium lauryl sulfate surfactant, mineral acid [sulfuric acid (H2SO4)], and a combination of surfactant with mineral acid in the aniline polymerization reaction are also carried. These salts were designated as PANI–NTSA–dodecyl hydrogen sulfate (DHS), PANI–NTSA–H2SO4, and PANI–NTSA–DHS–H2SO4, respectively. Interestingly, PANI–NTSA–DHS showed a highly ordered crystalline sample with a nanosphere morphology. These PANIs were used as electrode materials in supercapacitor applications. Among the four salts, the PANI–NTSA–DHS–H2SO4 material showed higher values of specific capacitance (520 F/g), energy (26 W h/kg), and power densities (200 W/kg) at 0.3 A/g. Moreover, 77% of the original capacitance was retained after 2000 galvanostatic charge–discharge cycles with a Coulombic efficiency of 98–100%. PANI–NTSA–DHS–H2SO4 was obtained in excellent yield with an excellent conductivity (6.8 S/cm) and a thermal stability up to 235°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42510.

Ring-opening polymerization of caprolactone using novel polyaniline salt catalyst

Hybrid composite of polyaniline metal oxide composite, polyaniline-dodecyl hydrogen sulfate salt with ferric oxide, was prepared for the first time via simple one-step process of oxidizing aniline with ferric tris(dodecyl sulfate). Ferric tris(dodecyl sulfate) acts as an oxidant, emulsifier, dopant for polyaniline and also source of ferric oxide. Polyaniline salt composites were prepared via aqueous, emulsion, and interfacial polymerization pathways. Polyaniline salt composite was successfully demonstrated as polymer based solid acid catalysts in the ring-opening polymerization of e-caprolactone for the first time. This methodology gave low molecular weight poly(e-caprolactone) (MW-4035) with highly crystalline polymer of flower petals like morphology in 52 wt% yield (with respect to the amount of e-caprolactone used). Advantages of this methodology are the use of easily synthesizable, easily handlable, recyclable, cheaper, and eco-friendly nature of the catalyst. POLYM. ENG. SCI., 55:2245–2249, 2015. © 2015 Society of Plastics Engineers

An impressive emulsion polymerization route for the synthesis of highly soluble and conducting polyaniline salts

We report a sophisticated emulsion polymerization route for the synthesis of polyaniline (PANI) salts. In this process, the chemical oxidative polymerization of aniline was carried out in the presence of two dopants i.e., dodecylbenzenesulfonic acid (DBSA) and sulfuric acid (H2SO4). The synthesized PANI salts were highly soluble in a large number and variety of common organic solvents (so far highest number of solvents including the less hazardous ethanol) and showed very good conductance. Presumably the presence of DBSA and sulfuric acid moieties, respectively, contributed toward the improvement in solubility and conductance. After optimization of the reaction parameters, the obtained polymers were systematically characterized with cyclic voltammetry, in situ conductance, in situ UV–vis spectroelectrochemical and intrinsic viscosity measurements. X-ray diffraction, TGA and SEM were used for further analysis. The materials showed very good electrochemical and electrochromic reversibility and high thermal stability (up to 500°C). Moreover, potentiodynamic measurements revealed that coatings of this polymer can provide extra ordinary resistance to the steel surfaces particularly against the harsh corrosive environment of the oceans.

Effect of polyaniline salts on the mechanical and corrosion properties of organic protective coatings

Abstract The aim of this work was to assess the effect of polyaniline salts (PANI-HA) with various dopant types on the mechanical and corrosion properties of organic protective coatings dependent on the pigment volume concentration. The doping acids used included phosphoric acid (H 3 PO 4 ), sulphuric acid (H 2 SO 4 ), hydrochloric acid (HCl), p-toluenesulphonic acid (PTSA), and 5-sulphosalicylic acid (CAS). The polyaniline salt types were described by their physico-chemical parameters. An epoxy ester resin was used as the binder for the organic coatings. The organic protective coatings included the various PANI-HA types. The prepared organic coatings were subjected to mechanical testing, corrosion tests and linear polarisation technique. Organic coatings achieved during mechanical tests comparable results regardless of the type of PANI dopant or PVC (pigment volume concentration) with the exception of organic coatings fulfilling the condition PVC = CPVC (critical pigment volume concentration) which exhibited decrease of mechanical resistance. The results of accelerated corrosion tests and techniques of linear polarisation testify that in particular the PVC parameter affects the resulting corrosion resistance. During those tests, the organic coatings exhibited improved corrosion resistance, particularly at low pigment volume concentrations (PVC = 0.1–5%) irrespective of the pigment used.

Calculation of particle size distribution of polyaniline salts using imagej

The detailed analysis of particle size distribution is desirable in several technical fields that ma-nipulate granular/particulate materials including size reduction. This article describes the mani-pulation of scanning electron micrographs (SEM) of polyaniline (PANI) salts using ImageJ soft-ware. The PANI salts were prepared by two servable methods i.e. emulsion polymerizations and inverse emulsion polymerizations. 1,2 The effects of these synthesis routs on the particles shape and size distributions of the PANI salts were evaluated. Slight differences in the particle shapes were observed for these PANI salts. The polymer synthesized by inverse emulsion polymerization method showed smaller size than the one prepared by emulsion polymerization method. This type of computer based image processing methods provide better solutions to practical measurement and size distribution analysis as compared to the time consuming and vague manual means.

Preparation and characterization of a new polyaniline salt with good conductivity and great solubility in dimethyl sulfoxyde

In this study, we propose a novel conducting and soluble polyaniline salt prepared by chemical polymerization in the presence of new doping agent (IAs). This last is prepared by sulphonation of itaconic acid (IA) with concentrated sulphuric acid in THF. The obtained doped polyaniline (PANI-IAs) is extremely soluble in dimethyl sulfoxyde (DMSO) at room temperature, in which the solubility reach 44 mg mL-1. The conductivity measurement of doped polyaniline powder precipitated in THF as dispersing medium gave a value of 0.13 S cm-1 when the emeraldine base form of polyaniline is fully protonated. The polyaniline salt sample is characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction, UV-Visible spectra and FTIR spectra.

A novel process of alcohol promoted polymerization of aniline to form a nanofibrous, fluorescent and highly crystalline polyaniline salt

Use of acid was replaced by alcohol in the polymerization of aniline to a highly crystalline, nanofibrous, fluorescent and conducting polyaniline salt.

Chemical synthesis and characterization of highly soluble conducting polyaniline in the mixtures of common solvents

This work presents the synthesis and characterization of soluble and conducting polyaniline PANI-PIA according to chemical polymerization route. This polymerization pathway leads to the formation of poly(itaconic acid) doped polyaniline salts, which are highly soluble in a number of mixtures between organic common polar solvents and water, the solubility reaches 4 mg mL-1. The effect of synthesis parameters such as doping level on the conductivity and the study of solubility and other properties of the resulting PANI salts were also undertaken. The maximum of conductivity was found equal to 2.48?10-4 S cm-1 for fully protonated PANI-EB. In addition, various characterizations of the synthesized materials were also done with the help of viscosity measurements, UV-vis spectroscopy, XRD, FTIR and finally TGA for the thermal properties behaviour.

Synthesis and Characterization of Low-Cost Electroactive Hybrid Composites Derived From Polyaniline and NiS

The synthesis and characterization of conducting polyaniline (PANI) salt and nickel sulfide (NiS) hybrid composites are reported in this study. The PANI-NiS hybrid composites showed nearly two orders of magnitude higher than that of pure PANI. The specific conductivities of PANI and PANI-NiS hybrid composites (2% and 20% by weight) were found to be 5.1 × 10−4, 1.6 × 10−2, and 3.8 × 10−2 S/cm. The polarity of Hall voltage of the hybrid composite was found to be negative indicating that the PANI-NiS composite is an n-type semiconductor. The composites pellets were characterized by XRD, SEM and FTIR and the results were compared.

Synthesis of highly crystalline polyaniline with the use of (Cyclohexylamino)-1-propanesulfonic acid for supercapacitor

Polyaniline (PANI) salt was prepared with 3-(Cyclohexylamino)-1-propanesulfonic acid (CAPS) as a novel dopant by aqueous polymerization pathway. Effects of sodium lauryl sulfate surfactant, mineral acid (H2SO4), and a combination of surfactant with mineral acid during the polymerization reaction were also determined. PANI-CAPS showed semicrystalline with flake-like morphology. The use of the sodium lauryl sulfate along with CAPS resulted in the formation of highly crystalline nanospheres with flake-like morphology. In order to find out the effect of surfactant, sodium lauryl sulfate was used in the reaction. The combination of sodium lauryl sulfate, CAPS, and H2SO4 brings about an extended nanosphere morphology. These polyaniline salts were used as electrode materials in the supercapacitor application, in a symmetric two-electrode cell configuration. The values of specific capacitance, energy, and power densities of PANI-CAPS-DHS-H2SO4 material at 2 mA cm−2 were 495 F g−1, 90 kJ kg−1, and 120 J Kg−1 s−1, respectively. Moreover, 85 % of the original capacitance was retained after 3,000 galvanostatic charge–discharge cycles with a coulombic efficiency of 96–99 %. The value of phase angle is close to 90 at low frequencies, indicating a good capacitive behavior.

Nanosphere of Semicrystalline Polyaniline Powder: An Effective, Versatile, and Reusable Catalyst for Hantzsch Reaction

Polyaniline salt containing 1-hydroxyethane-1,1-diphosphonic acid with nanosphere morphology in semicrystalline powder form was successfully synthesized by interfacial polymerization pathway and demonstrated as polymer based acid catalyzed in the synthesis of 1,4-dihydropyridines and polyhydroquinoline derivatives. This catalyst promotes the reaction under solvent free condition in excellent yield in 10 min with recyclability. The advantages of this methodology are the easy synthesis of polymer containing acid group catalyst in powder form having easily handlable, efficient, versatile, and reusable nature.

Purification of a conducting polymer, polyaniline, for biomedical applications

A conducting polymer, polyaniline, was prepared in globular and nanotubular morphologies. The protonated forms were converted to the corresponding bases and both types of samples were tested for cytotoxicity. The polyanilines were then suspended in N-methylpyrrolidone or in concentrated sulphuric acid, and the soluble parts were precipitated into methanol acidified with sulphuric acid. Such a dissolution/precipitation cycle was tested as a purification procedure for polyaniline, which would remove the potential low-molecular-weight components. The original morphology of polyaniline was destroyed in soluble part (18–24wt.%) but maintained in the fraction insoluble in N-methylpyrrolidone. The fraction soluble in sulphuric acid was higher (56–64wt.%). The original morphology converted to fragments after reprecipitation, and the samples became amorphous. The conductivity was reduced on average by two orders of magnitude. FTIR spectroscopy was used to assess the molecular structure, hydrogen bonding, and their changes. The cytotoxicity of polyaniline salt determined on mouse embryonic fibroblast cell line NIH/3T3 was reduced after reprecipitation from N-methylpyrrolidone when compared to the initial polymer and showed the absence of cytotoxicity at the extract concentration of 5 and 10% in the case of globular and nanotubular polymer, respectively. A corresponding positive effect was not observed for polyaniline reprecipitated from sulphuric acid.

Polyaniline salts as polymer‐based solid acid catalyst for low molecular weight poly(lactic acid)

ABSTRACTPolymer‐based solid acid catalyst, polyaniline (PANI) salt, is used for the first time to synthesize polymer. In continuation of our work to synthesize organic chemicals using PANI‐based solid acid catalyst, in this work, polylactic acid is synthesized by the condensation polymerization of lactic acid using PANI salts. PANI salts are characterized by FTIR, FE‐SEM, and TGA analyses. Polymerization of lactic acid in xylene solvent at 140°C for 24 h with the use of very low amount of PANI catalysts gave polylactic acid (PLLA) in the order: PANI‐MSA (46%) > PANI‐TFA (33%) > PANI‐Bi(OTf)3 (27%) > PANI‐Cu(OTf)2 (20%) > PANI‐Yb(OTf)3 (15%). Molecular weights of PLLA synthesized using PANI‐MSA and PANI‐TFA are found to be 4385 and 4830, respectively. This methodology gives highly crystalline polymer with mushroom cap‐like morphology. Advantage of this methodology is the use of easily synthesizable, recyclable, easily handlable, cheaper, and eco‐friendly nature of the catalyst. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41147.

Reprotonated polyanilines: The stability of conductivity at elevated temperature

Abstract Reprotonation of polyaniline base with various acids opens a way to conducting materials widely differing in physical properties. The thermal stability of the resulting polyaniline salts was tested by measurements of the conductivity at 125 °C for up to 500 h. Polyaniline sulfate was the most stable and its resistivity increased only by 3.6 times after that time. The stability differed considerably depending on the acid used for reprotonation. The room-temperature conductivity of polyaniline salt is determined by the strength of the acid and its ionic bond with the imine nitrogen in polyaniline. The thermal stability of conductivity, however, is controlled by the ability of the acid to constitute hydrogen bonds with the secondary amine nitrogens in polyaniline. For that reason, oxygen-containing counter-ions, such as sulfates or sulfonates, produce more stable salts with polyaniline, compared with polyaniline protonated with, e.g., hydrochloric acid. The presence of hydroxyl group in the counter-ions also enhances the thermal stability of the polyaniline salt. These conclusions are supported by the analysis of FTIR spectra.

Electrochemical sensor based on polyaniline nanofibers/single wall carbon nanotubes composite for detection of malathion

Detection of malathion (organophosphorous pesticide) based on composite of polyaniline nanofiber and single walled carbon nanotube deposited onto graphite electrode was investigated. >Fourier transforms infrared and UV–vis absorption spectra, X-ray diffraction, scanning electron microscope and cyclic voltammetry were used to characterize the prepared polyaniline. Malathion concentration was detected using differential pulse voltammetry technique at polyaniline–single wall carbon nanotubes modified graphite electrode. The fabricated polyaniline–single wall carbon nanotubes modified graphite electrodes have exhibited higher accuracy toward the reduction of malathion. Malathion was found to exhibit one well-defined reduction peak at pH 7. A linear response to malathion in the concentration range from 2.0×10−7M to 14.0×10−7M was observed. The minimum detection limit in the linear range for the modified electrodes was 2.0×10−7M malathion. It was found that the single wall carbon nanotubes improved the sensitivity of the polyaniline salt graphite electrode from 5.4mA/μM for polyaniline salt to 7.22mA/μM.

Electrocatalytic Activity of Carbonized Nanostructured Polyanilines for Oxidation Reactions: Sensing of Nitrite Ions and Ascorbic Acid

A comparative study of the electrocatalytic activity of nitrogen-containing carbon nanomaterials, prepared by the carbonization of nanostructured polyaniline (PANI) salts, for the electrooxidation reactions is presented. Nanostructured PANI salts were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous solution in the presence of 5-sulfosalicylic acid (PANI-SSA), 3,5-dinitrosalicylic acid (PANI-DNSA) as well as without added acid (PANI), and subsequently carbonized to c-PANI-SSA, c-PANI-DNSA and c-PANI, respectively. Glassy carbon tip was modified with nanostructured c-PANIs and used for the investigation of sensing of nitrite and ascorbic acid in aqueous solutions as model analytes by linear sweep voltammetry. All three types of the investigated c-PANIs gave excellent response to the nitrite ions and ascorbic acid electrooxidation. The lowest peak potential for nitrite ion oxidation exhibited c-PANI (+0.87V vs. SCE), and for ascorbic acid oxidation both c-PANI and c-PANI-SSA (ca.+0.13V vs. SCE). Electrochemical data were correlated with structural and textural data obtained by Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, elemental and nitrogen sorption analysis.

Synthesis and characterization of polyaniline and poly(aniline-co-o-nitroaniline) using vibrational spectroscopy

Due to the advantages of material abundance and synthetic simplicity, polyaniline can be used as a high capacity cathode material. However, its practical application in battery has been hindered by poor electrochemical utilization and cycling instability. To solve these problems, we synthesized the Polyaniline-co-o-nitroaniline aniline. The copolymers were synthesized for 1:1 and 1:4M ratios of aniline and o-nitroaniline in acidic medium using ammonium persulfate as oxidant and their properties were compared with that of polyaniline. The prepared samples have been characterized using number of techniques including Raman spectroscopy, FTIR, UV–vis, and conductivity. The polymers showed less electrical conductivity than polyaniline. Unlike polyaniline, the presence of nitro group caused higher frequency dependence of electrical conductivity. The FTIR bands at 1560, 1306 and 1148cm−1 are corresponding to the polyaniline salt. The Raman band observed in the range of 1100–1140cm−1 is the characteristic of conductive polyaniline and is due to the charge delocalization on the polymer backbone.