Synthesis of electroconductive polyaniline using immobilized laccase

A new method for synthesis of the conductive complex between polyaniline (PANI) and poly(2-acrylamido-2-methyl-1-propanosulfonic acid) (PAMPS) was proposed; in this method, the immobilized laccase from the basidiomycete Trametes hirsuta is used as a biocatalyst for aniline oxidative polymerization. The conditions for laccase immobilization on CM cellulose by bifunctional Woodward’s reagent were optimized. The catalytic properties of immobilized and native laccases were compared. The immobilized laccase appeared an efficient catalyst for the oxidative radical polymerization of aniline on polysulfonic acid matrix at 4°C. It was demonstrated that the immobilized enzyme could be repeatedly used for enzymatic synthesis of this polymer. Several spectral characteristics of the PANI/PAMPS complexes synthesized at various pH values were studied. The conductance of PANI specimens produced using immobilized laccase as a catalyst was 13 mS/cm.     

Preparation and characterization of polyaniline/chitosan blend film

Films consisting of a blend of a chitosan hydrogel and a conductive polymer, polyaniline (PANI), were prepared and characterized for their electrical and mechanical properties. Polyaniline in emeraldine base (EB) form was dispersed in chitosan solution and blend films were obtained by solution casting. The PANI particles in the blend films were then doped with HCl where we observed reductions in the film tensile strength and Young's modulus by about 30%, but the films electrical conductivity increased by 6 orders of magnitude. The highest electrical conductivity of the blend films was of the order 10⁻⁴ S/cm. The electrical and mechanical properties of the films varied with polyaniline content, acid dopant type, acid dopant concentration, and doping time.     

Micellar laccase-catalyzed synthesis of electroconductive polyaniline

A method of enzymatic synthesis of electroconductive polyaniline on the micelles of dodecylben-zenesulfonic acid sodium salt (DBSNa) is proposed. The high potential laccase from the basidiomycete Trametes hirsuta was used as a biocatalyst. The conditions for polyaniline synthesis were optimized (pH 4.0; reagent concentrations, 10-20 mM; and aniline/DBSNa ratio, 2: 1). The resulting product was electrochemically active in the range of potentials from -200 to 600 mV, electroconductive, and capable of reversible dedoping with a change in pH of solution.     

Coloured and low conductive fabrics by in situ laccase-catalysed polymerization

Coloured and conductive fabrics were obtained through “in situ” laccase polymerization of catechol and p-phenylenediamine under high-pressure homogenization. Both monomers, catechol and p-phenylenediamine, were polymerized by different laccase forms, namely native, PEGylated and Epoxy-PEGylated. All the catalysts were placed inside a textile fabric bag which served simultaneously as enzyme support and as substrate for coating with the newly produced polymers. The PEGylated laccase forms gave rise to a higher amount of oligomers/polymers and higher colouration level of polyethylene terephthalate (PET), cotton and wool fabrics compared to native laccase. Both functional polymers were able to confer conductivity to the substrates however in a different extent. Fabrics coated with poly(p-phenylenediamine) present higher conductivity, rather due to its polymerized structure than to the amount of polymer produced by enzyme catalysis. Herein a green approach was presented to produce polyphenols with increased fixation onto different textile substrates. These substrates reach high levels of colouration and good fastness behaviour after washing.     

Micellar laccase-catalyzed synthesis of electroconductive polyaniline

A method of enzymatic synthesis of electroconductive polyaniline on the micelles of dodecylbenzenesulfonic acid sodium salt (DBSNa) is proposed. The high potential laccase from the basidiomycete Trametes hirsuta was used as a biocatalyst. The conditions for polyaniline synthesis were optimized (pH 4.0; reagent concentrations, 10–20 mM; and aniline/DBSNa ratio, 2 : 1). The resulting product was electrochemically active in the range of potentials from ?200 to 600 mV, electroconductive, and capable of reversible dedoping with a change in pH of solution.     

Biomimetic synthesis of a water soluble conducting molecular complex of polyaniline and lignosulfonate

A new biomimetic route for the synthesis of a conducting molecular complex of polyaniline (Pani) and a natural polyelectrolyte, lignosulfonate (LGS) is presented. A poly(ethylene glycol) modified hematin (PEG-hematin) was used to catalyze the polymerization of aniline in the presence of LGS to form a Pani/LGS complex. UV-vis, FTIR, conductivity and TGA studies for the LGS-polyaniline complex indicate the presence of a thermally stable and electrically conductive form of polyaniline. Also the presence of LGS in this complex, an inexpensive byproduct from pulp processing, provides a unique combination of properties such as electronic conductivity, processability and biodegradability. The use of this conductive complex for corrosion protection is also proposed.     

Heterogeneous preparation of cellulose–polyaniline conductive composites with cellulose activated by acids and its electrical properties

A series of conductive composites cellulose–polyaniline (PANI) were heterogeneously synthesized by chemical oxidative polymerization of aniline with native cellulose activated by various acids. The chemical structure and morphology of the composites were examined by FT-IR analysis and TEM. TGA was used to study their thermal properties. The composites prepared using the di-basic acids exhibited more favorable conductivity than the composites prepared using the monobasic acids. The content of PANI increased with increasing of activation time, and while the conductivity decreased because of the aggregation of PANI particles at the activation time range from 50 to 120 min. Both the PANI content and the electrical conductivity increased with an increase of the amount of aniline, and reached the maximum values at the 0.5 g aniline, respectively. The acids were able to successfully activate cellulose and lead to the improvement of the accessibility and reactivity of the O–H groups. The composites were highly stable compared to pure cellulose due to the safeguard from PANI slices. This work provided a facile method for the synthesis of cellulose–polyaniline conductive composites with excellent conductivity.     

Structural and electrical properties of paper-polyaniline composite

Conducting polymers have generated a great deal of interest because of their physical and chemical properties as well as their potential application in industry particularly in packaging applications. However one of short comings of most conducting polymer is that they are often formed as intractable films that are difficult to process. To overcome this problem we have incorporated conducting polymer, namely polyaniline into sheets of paper in order to create new composite material which combine the universal properties of paper product with the chemical and electrically conducting properties of the conducting polymer. Paper conducting polymer composite have been prepared by polymerizing aniline directly onto the paper sheet using ammonium peroxydisulfate (APS) as an oxidant at different temperatures. The prepared composite was characterized by FT-IR and SEM. The thermo-oxidative degradation was studied by thermo gravimetric analysis (TGA); electrical conductivities measurements of the composites were significantly increased over those of the precursor paper.     

Controlled Synthesis and Energy Applications of One‐Dimensional Conducting Polymer Nanostructures: An Overview

The past decade has witnessed increasing attention in the synthesis, properties, and applications of one‐dimensional (1D) conducting polymer nanostructures. This overview first summarizes the synthetic strategies for various 1D nanostructures of conjugated polypyrrole (PPy), polyaniline (PANI), polythiophene (PTh), poly(p‐phenylenevinylene) (PPV) and derivatives thereof. By using template‐directed or template‐free methods, nanoscale rods, wires/fibers, belts/ribbons, tubes, arrays, or composites have been successfully synthesized. With their unique structures and advantageous characteristics (e.g., high conductivity, high carrier mobility, good electrochemical activity, large specific surface area, short and direct path for charge/ion transportation, good mechanical properties), 1D conducting polymer nanostructures are demonstrated to be very useful for energy applications. Next, their applications in solar cells, fuel cells, rechargeable lithium batteries, and electrochemical supercapacitors are highlighted, with a strong emphasis on recent literature examples. Finally, this review ends with a summary and some perspectives on the challenges and opportunities in this emerging area of research.     

Design and development of low cost polyurethane biopolymer based on castor oil and glycerol for biomedical applications

In the current study, we present the synthesis of novel low cost bio‐polyurethane compositions with variable mechanical properties based on castor oil and glycerol for biomedical applications. A detailed investigation of the physicochemical properties of the polymer was carried out by using mechanical testing, ATR‐FTIR, and X‐ray photoelectron spectroscopy (XPS). Polymers were also tested in short term in‐vitro cell culture with human mesenchymal stem cells to evaluate their biocompatibility for potential applications as biomaterial. FTIR analysis confirmed the synthesis of castor oil and glycerol based PU polymers. FTIR also showed that the addition of glycerol as co‐polyol increases crosslinking within the polymer backbone hence enhancing the bulk mechanical properties of the polymer. XPS data showed that glycerol incorporation leads to an enrichment of oxidized organic species on the surface of the polymers. Preliminary investigation into in vitro biocompatibility showed that serum protein adsorption can be controlled by varying the glycerol content with polymer backbone. An alamar blue assay looking at the metabolic activity of the cells indicated that castor oil based PU and its variants containing glycerol are non‐toxic to the cells. This study opens an avenue for using low cost bio‐polyurethane based on castor oil and glycerol for biomedical applications.     

Understanding the Effects of Molecular Dopant on n‐Type Organic Thermoelectric Properties

Molecular doping is a powerful method to fine‐tune the thermoelectric properties of organic semiconductors, in particular to impart the requisite electrical conductivity. The incorporation of molecular dopants can, however, perturb the microstructure of semicrystalline organic semiconductors, which complicates the development of a detailed understanding of structure–property relationships. To better understand how the doping pathway and the resulting dopant counterion influence the thermoelectric performance and transport properties, a new dimer dopant, (N‐DMBI)₂, is developed. Subsequently, FBDPPV is then n‐doped with dimer dopants (N‐DMBI)₂, (RuCp*mes)₂, and the hydride‐donor dopant N‐DMBI‐H. By comparing the UV–vis–NIR absorption spectra and morphological characteristics of the doped polymers, it is found that not only the doping mechanism, but also the shape of the counterion strongly influence the thermoelectric properties and transport characteristics. (N‐DMBI)₂, which is a direct electron‐donating dopant with a comparatively small, relatively planar counterion, gives the best power factor among the three systems studied here. Additionally, temperature‐dependent conductivity and Seebeck coefficient measurements differ between the three dopants with (N‐DMBI)₂ yielding the best thermoelectric properties. The results of this study of dopant effects on thermoelectric properties provide insight into guidelines for future organic thermoelectrics.     

A Three‐Dimensionally Interconnected Carbon Nanotube–Conducting Polymer Hydrogel Network for High‐Performance Flexible Battery Electrodes

High‐performance flexible energy‐storage devices have great potential as power sources for wearable electronics. One major limitation to the realization of these applications is the lack of flexible electrodes with excellent mechanical and electrochemical properties. Currently employed batteries and supercapacitors are mainly based on electrodes that are not flexible enough for these purposes. Here, a three‐dimensionally interconnected hybrid hydrogel system based on carbon nanotube (CNT)‐conductive polymer network architecture is reported for high‐performance flexible lithium ion battery electrodes. Unlike previously reported conducting polymers (e.g., polyaniline, polypyrrole, polythiophene), which are mechanically fragile and incompatible with aqueous solution processing, this interpenetrating network of the CNT‐conducting polymer hydrogel exibits good mechanical properties, high conductivity, and facile ion transport, leading to facile electrode kinetics and high strain tolerance during electrode volume change. A high‐rate capability for TiO₂ and high cycling stability for SiNP electrodes are reported. Typically, the flexible TiO₂ electrodes achieved a capacity of 76 mAh g^–1 in 40 s of charge/discharge and a high areal capacity of 2.2 mAh cm^–2 can be obtained for flexible SiNP‐based electrodes at 0.1C rate. This simple yet efficient solution process is promising for the fabrication of a variety of high performance flexible electrodes.     

Enzymatic synthesis of electroconductive biocomposites based on DNA and optically active polyaniline

Electroconductive interpolymer polyaniline complexes are synthesized on the DNA matrix, using the method of oxidative polymerization of aniline with two different biocatalyzers: horseradish root peroxidase and micropiroxidase-11 biomimetic. The spectral characteristics and morphology of the acquired biocomposites have been studied. The stereospecificity of the acquired samples of interpolymer complexes is shown, depending on the biocatalyzers used. The results acquired indicate the important role of a biocatalyzer in the formation of the twist direction of an electroconductive polymer spiral on the DNA matrix; i.e., the optical activity of the polymer samples acquired is apparently associated with the biocatalyzer properties.     

Superabsorbent conducting hydrogel from poly(acrylamide-aniline) with thermo-sensitivity and release properties

Interpenetrating networks (IPN) poly(acrylamide-aniline) polymer was synthesized by a two-steps aqueous polymerization method, which aniline monomer was absorbed in the network of polyacrylamide and followed by a polymerization reaction between aniline monomers. The poly(acrylamide-aniline) hydrogel possessed a conductivity of 25.28 mS cm⁻¹. An interpenetrating network structure model with a three-dimensional network of polyacrylamide and a one-dimensional chain of polyaniline for poly(acrylamide-aniline) conducting hydrogel was proposed, and a conduction mechanism with charge carriers (protons) hopping along the polyaniline chain was suggested. The poly(acrylamide-aniline) hydrogels have predominant thermo-sensitivity. Poly(acrylamide-aniline) hydrogels possess loading and releasing properties, an anomalous release mechanism is found.     

Enzymatic synthesis of electroconductive biocomposites based on DNA and optically active polyaniline

Electroconductive interpolymer polyaniline complexes are synthesized on the DNA matrix, using the method of oxidative polymerization of aniline with two different biocatalyzers: horseradish root peroxidase and micropiroxidase-11 biomimetic. The spectral characteristics and morphology of the acquired biocomposites have been studied. The stereospecificity of the acquired samples of interpolymer complexes is shown, depending on the biocatalyzers used. The results acquired indicate the important role of a biocatalyzer in the formation of the twist direction of an electroconductive polymer spiral on the DNA matrix; i.e., the optical activity of the polymer samples acquired is apparently associated with the biocatalyzer properties.     

Investigation of a green process for the polymerization of catechin

Flavonoids are polyphenolic secondary plant metabolites which possess antioxidant and anti-inflammatory properties. Besides, they have been shown to exhibit increased antioxidant properties in their polymerized form. Catechins are one of the attractive class of flavonoids which belong to the group of flavan-3-ols. Polymerization of catechins have been investigated in numerous studies indicating the requirement of certain amount of organic solvent to provide the solubility of the monomer. However, many research projects have been conducted recently to replace toxic organic contaminants of the processes with environmentally friendly solvents. In this aspect, deep eutectic solvents (DESs) that are regarded as “green solvents” have been studied extensively in various enzyme catalyzed reactions. In the present study, we focused on establishing a green pathway for laccase catalyzed polycatechin synthesis by replacing organic solvent content with DESs as green solvents. For this aim, various parameters were investigated, such as DES types and concentrations laccase amount and reaction time. Consequently, the highest molecular weight polycatechin was obtained using 5% (v/v) B–M, 125?U laccase in 1?hr of reaction time, at 30°C, as 4,354?±?678?g?mol^?1. Corresponding X/XO inhibitory activity and superoxide radical scavenging activities were achieved as, 59 and 50%, respectively.     

Miniaturized systems for evaluating enzyme activity in polymeric membrane bioreactors

Enzyme‐coated polymeric membranes are versatile catalysts for biofuel production and other chemical production from feedstock, like plant biomass. Such bioreactors are more energy efficient than high temperature methods because enzymes catalyze chemical reactions near room temperature. A major challenge in processing plant biomass is the presence of lignin, a complex aromatic polymer that resists chemical breakdown. Therefore, membranes coated with enzymes such as laccase that can degrade lignin are sought for energy extraction systems. We present an experimental study on optimizing an enzyme‐based membrane bioreactor and investigate the tradeoff between high flow rate and short dwell time in the active region. In this work, zero flow rate voltammetry experiments confirm the electrochemical activity of Trametes versicolor laccase on conductive polymer electrodes, and a flow‐through spectroscopy device with laccase‐coated porous nylon membranes is used with a colorimetric laccase activity indicator to measure the catalysis rate and percent conversion as a function of reactant flow rate. Membrane porosity before and after laccase coating is verified with electron microscopy.     

Laccase-catalyzed oxidative polymerization of aniline dimer (N-phenyl-1,4-phenylenediamine) in aqueous micellar solution of sodium dodecylbenzenesulfonate

We have studied oxidative polymerization of aniline dimer (N-phenyl-1,4-phenylenediamine) catalyzed by high-redox potential laccase isolated from the fungi Trametes hirsuta (Wulfen) Pilát CF-28. Enzymatic aniline dimer polymerization was performed in aqueous micellar solution of sodium dodecylbenzenesulfonate, the atmospheric oxygen serving as an oxidizer. The resultant dispersion was stable for at least 6 months. The products synthesized were characterized using Fourier transform infrared and UV–vis spectroscopies. MALDI TOF analysis has shown that aniline dimers polymerize to mainly form aniline oligomers with the m/z ratio up to 2180, which corresponds to a polymerization degree of 24 (in terms of aniline subunits). Enzymatically formed aniline oligomers consist for the most part of para-directed units in the form of emeraldine salt. The end product structure depends on the reaction medium pH. Transmission electron microscopy has revealed granular nanoparticles of the reaction product.     

Molecularly imprinted polyaniline molecular receptor–based chemical sensor for the electrochemical determination of melamine

Molecularly imprinted polymer‐modified glassy carbon electrode (GCE)‐based electrochemical sensor is prepared using the electropolymerization of aniline in the presence of melamine (MA) as a template. In this work, the advantages of molecularly imprinted conducting polymers (MICPs) and electroanalytical methods were combined to obtain an electronic device with better performances. The sensor performance was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV) with the linear range of 0.6‐16 × 10^?9M, quantification limit of 14.9 × 10^?10M, and detection limit of 4.47 × 10^?10M (S/N = 3). The selectivity of the sensor was tested in the presence of acetoguanamine (AGA), diaminomethylatrazine (DMT), casein, histidine, and glycine interfering molecules taken at the triple concentration with MA that demonstrated too small current response compared with that of the analyte indicating high specificity of the sensor towards the template. The sensor was successfully applied to determine MA in infant formula samples with significant recovery greater than 96% and relative standard deviation (RSD) less than 4.8%. Moreover, the good repeatability, recyclability, and stability make this sensor device promising for the real‐time monitoring of MA in different food stuffs.