جستجوی مقالات مرتبط با کلیدواژه "conducting polymer" در نشریات گروه "شیمی"

The implementation of photocatalytic approaches to treat petroleum-derived waste e.g., oil spills has recently gained popularity. While using dispersants to treat marine oil spills has proven effective, traditional dispersants only achieve monolayer oil dispersion. This study proposes modified metal semiconductors with aminophenol formaldehyde (APF), an efficient particle dispersant with photocatalytic activity, for removing oil spills from aqueous environments. Effective photocatalytic nanocomposites were synthesized through a simple solvothermal process, combining TiO2 and Fe3O4 metal semiconductors in a conducting APF polymer (MAPF and TAPF). These materials can offer high adsorption capacity and hydrocarbon photo-degradation. Both MAPF and TAPF showed strong photocatalytic performance, achieving up to 74% and 86%, respectively. This combination of dispersion, adsorption, and photocatalysis offers a novel approach to managing oil spills in marine environments.

Dopamine (DA) is a vital neurotransmitter having key roles in regulating various biological functions in animals and the sensitive and selective monitoring of DA in biological fluid is of high significance. Herein, poly(1-naphthylamine)–graphene oxide (PNA-20GO) nanocomposite containing 20 % GO by weight obtained by the in-situ chemical oxidative polymerization of 1-naphthylamine in the presence of GO was utilized to develop an economical electrochemical sensor for DA by modifying Carbon Paste Electrode (CPE) with prepared PNA-20GO nanocomposite. The electrochemical characterization of the PNA and PNA-20GO was performed with Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopic (EIS) studies. The electrochemical response and charge transfer kinetics were significantly improved for the PNA-GO-modified CPE compared to PNA-modified CPE which was evidenced by the comparatively lower diameter of the semicircle region in the Nyquist plot obtained from EIS studies and better current response for the PNA-GO modified CPE than PNA modified or bare CPE in the corresponding CV curves. The enhanced electrochemical characteristics were credited to the increased surface area and synergistic charge transfer interactions between the PNA and GO. Furthermore, it was observed that PNA-GO modification could trigger the diffusion-controlled electrochemical oxidation of DA over CPE. The demonstrated PNA-GO modified DA sensor could show the linear current response for DA concentration ranging from 1-100 µM. The sensor exhibited high sensitivity (1094 µA/(mM.cm2)) with a low detection limit of 0.23 µM. The present DA sensor could exhibit acceptable stability and selectivity over common interfering molecules like creatine, ascorbic acid, and uric acid.

New electrically conducting composite polymers consisting of poly (2-hydroxy-5-methyl anline) self-doped with poly (o-toluidine) were prepared within the polymer matrix by in situ polymerization of aniline. The conversion yield of self-doped poly[2-hydroxy-5-methyl anline-co-(o-toluidine)] into doped poly[2-hydroxy-5-methyl anline-co-(o-toluidine)] by treatment with HCl while structural confirmation of the synthesized polymer was sought by Fourier Transform Infrared and thermogravimetric analysis. Conductivity of the polymers was measured by two probe method. As for Activation energy, Ea for dc conduction was deduced and its value was found to be the fraction of an eV for all the polymers. By increasing doping content, Ea decreased and σ increased. The result showed that the conductivity increased with increasing temperature in the order: Doping P(OT-co-HMA)> P(OT-co-HMA)> PHMA >POT, showing conducting behavior and activation energy of polymers was estimated.

Facile and fast hydrothermal copolymer synthesis of aniline and sulphanilic acid was studied at the presence of ammonium persulphate as an oxidising agent for polymerisation reaction of 1:1 mole ratios of aniline to sulphanilic acid. Physiochemical properties of poly (An-co-SA) copolymer micro particles were scientifically analyse using numerous key techniques. The toxic metal ions spontaneous subtraction efficiency of the poly (An-co-SA) copolymer micro particles was optimized. Results recommended that, the properly controlling the polymerization under the hydrothermal method was a simple but helpful way to significantly improve the conductivity of the copolymers of aniline and sulphanilic acid monomer copolymerized. The poly (An-co-SA) copolymer micro particles could be very appropriate to exclusion and revitalization of metal ions which was toxic to environment from wastewater.

Current work proposes an inimitable composite, with great electrical conductivity and quite enhanced surface area, (including conducting polymers (poly (cathechol)), Cu2O–carbon dots and green synthesized gold nanoparticles) for detecting acute carcinoembryonic antigen. At current work, the electropolymerization was offered instead of enzyme-catalyzed polymerization of poly (catechol). Four cost-effective electrochemical techniques (Differential Pulse Voltammetry, Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Crono amperometry) were engaged to investigate aptasensors construction, immobilization, hybridization, sensitivity, selectivity, repeatability, long-term stability and real PCR sample detections. According to the data, the values of Ipeak is linearly related to the logarithm of the concentrations of carcinoembryonic antigen in the range from 1.0 pg mL-1 to 0.001 g mL-1, with a detection limit of 0.19 pg mL-1 for the target antigen (carcinoembryonic antigen).

An electrochemical potentiometric sensor was introduced for Fluoxetine (FLX) analysis in pharmaceutical formulations using conducting polymer coated on a solid-state contact. FLX is one of the antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. For this purpose, pyrrole was electrochemically polymerized on the surface of a solid contact made of graphite to form a thin layer of poly(pyrrole) (PPy). After this step, a thin layer of another polymeric composite composed of poly(vinyl chloride), dibutyl phthalate and ion-pair compound of FLX and phenyl borate was covered on the treated surface. The modified graphite rod was finally used as a working electrode in a potentiometric cell assembly. Linear concentration range of 1.0×10−6 to 1.0×10−3 mol L-1, lower detection limit of 6.3×10−7 mol L-1, 8s response time, and two months lifetime were the characterizations of the proposed sensor. Finally, FLX content of some pharmaceutical samples were analyzed by the prepared sensor accurately and precisely.

Conducting polymers (CPs) have been gathering a great interest in academia and industry by providing the opportunity of combining the electrical properties of a semiconductor and metals with the traditional advantages of conventional polymers such as easy and low cost preparation and fabrication. In this review we examined the conducting polymers-based composites for supercapacitor and batteries, such as conducting polymer-based binary, ternary, and quaternary composites. For their applications in energy storage field, we critically review the development of their applications and the general design rules for energy storage devices including supercapacitors, lithium and other -ions batteries, and their current limitations and future potential to advance energy storage technologies. It is expected that this review will help to improve the knowledge about this conducting polymer and consequently lead to new research fields.

Porphyrins are a group of heterocyclic macrocycle organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (=CH−). Porphyrins have attracted much attention because of their unique structures and a wide spectrum of very useful physicochemical and biological properties, such as anion binding, stabilization of metal ions with unusual oxidation states, electron transfer, and construction of peculiar supramolecular assemblies. The synthesis of electroactive and water-soluble polymers were accomplished with water-soluble metal(III) porphyrins in the presence of a template. The polymerization by matelloporphyrin is simple (one-step), chemically mild, and environmentally benign and requires minimal separation. This approach provides a distinct advantage over similar reactions employing native enzymes due to higher stability and lower price of the catalysts.

The possibility of daclatasvir electrochemical detection, assisted by conducting polymer-based sulfoacid, was analyzed by theoretical point of view. It was shown, that the conducting polymer sulfoacid may serve as an excellent electrode modifier, permitting the use of more flexible pH-window for analysis. The steady-state may be maintained stable in the vast parameter region. The electroanalytical response has to be clear and easy to interpret. The possibility for electrochemical instabilities (electrochemical oscillations and monotonic instability) in this system has also been studied.

Polyaniline/maghemite magnetic nanocomposite (PANI/γ -Fe2O3 MNC) was used as active agents for removal of lead ions from aqueous media. Chemical co-precipitation method was used to prepare the maghemite nanoparticles. Subsequently, the MNC was synthesized through polymerization of aniline. It was characterized by FT-IR.The efficiency of this MNC was estimated for Pb (II) removal by using batch method. The results showed that optimum conditions for lead removal were found to be at pH of 6, adsorbent dosage of 0.04 g and equilibrium contact time of 90 min. The kinetic of adsorption system have been studied based on the assumption of a pseudo-second order rate law. The adsorption isotherms were examined. The Freundlich adsorption isotherm model was found to represent the equilibrium adsorption isotherm better than Langmuir isotherm. The thermodynamic studies indicated that the adsorption was spontaneous and endothermic process for lead.

The nanocomposites of polythiophene and carboxylated multiwalled carbon nanotubes (MWCNTs) were synthesized by in-situ chemical oxidative polymerization method using anhydrous ferric chloride (FeCl3) as an oxidant. The MWCNTs functionalized and ultrasonicated to obtain uniform dispersion within the polythiophene matrix. Field emission scanning electron microscopy was used to characterize the morphology of the nanocomposite. X-Ray diffraction, Fourier Transform Infrared Spectroscopy, Raman spectroscopy, and thermogravimetric analysis were used to characterize the synthesized MWCNT-polythiophene nanocomposites. It was found that in-situ polymerized polythiophene layer matrix was formed on carboxylated MWCNT and there was uniform dispersion of MWCNTs within the polythiophene matrix with significant interaction between polythiophene and MWCNTs. The sensitivity response of the prepared MWCNT-polythiophene nanocomposite sensors was studied in using Ammonia gas. The synergistic effects of the polythiophene-coated MWCNTs improve the gas sensing properties. Results showed that the sensitivity increased with ammonia concentration and it is also affected by the MWCNT content in polythiophene matrix. Furthermore, the sensor in pellet form reported here is robust, cost effective, and relatively stable at room temperature.

An electrochemical sensor was prepared by the modification of the carbon paste electrode (CPE) with a synthesized nanocomposite. The structure and morphology of the nanocomposite which was prepared by combination of poly pyrrole and copper oxide nanoparticles (PPy/CuO) was studied. This nanocomposite showed good electrocatalytic activity; so that the nanocomposite based electrochemical sensor (CPE-PPy/CuO) exhibited an excellent electroanalysis signals toward oxidation of dopamine (DA) and acetaminophen (AC). This effect is concluded from the high conductivity, low electron transfer resistance and catalytic effect of the PPy/CuO. The fabricated sensor had a lower overvoltage and higher electrical current respect to the bare CPE, for both DA and AC. Also, this sensor can resolve the overlapped anodic peaks of DA and AC and therefore it was used in the simultaneous determination. The calibration plots with wide linear ranges and suitable sensitivity was obtained for DA and AC by differential pulse voltammetry. Also good detection limits were found including 0.020 μM for DA and 0.025 μM for AC. Finally, the electrochemical sensor was used for determination in real samples.

A new strategy was developed to investigate conducting polymer poly(3,4-ethylenedioxy)thiophene:poly(styrenesulfonate) (PEDOT:PSS) properties and potential for enzymatic electrochemical detection of l-phenylalanine. PEDOT:PSS was blended with polyvinyl alcohol (PVA) and further treated with glutaraldehyde (GA) to produce new conducting polymer composite films of PEDOT:PSS/PVA-GA on indium(tin) oxide (ITO)-coated glass slides. Phenylalanine dehydrogenase (PheDH) was covalently immobilized on the glutaraldehyde modified conducting polymer composite films to produce PEDOT:PSS/PVA-GA-PheDH films. Using this strategy, PEDOT:PSS remained chemically unmodified and its electrical properties was maintained in a matrix containing glutaraldehyde modified polyvinyl alcohol. Electrochemical behavior of the conducting polymer composite films, before and after enzyme immobilization, was investigated using a potentiostat/galvanostat. Cyclic voltammograms showed an oxidation peak of about 0.63 V for PEDOT:PSS/PVA-GA (PEDOT:PSS to PVA ratio=1/1) and about 0.73 V forPEDOT:PSS/PVA-GA-PheDH in different concentrations of L-phenylalanine in Glycine/KCl/KOH buffer solution (100 mM, pH=10.4). The redox properties of PEDOT:PSS/PVA-GA films which is attributed to oxidation of PEDOT seems to contribute to electron transfer to the electrode during enzymatic reaction. Results showed that the system is suitable for determination of L-Phe in human urine for people with phenylketonuria.

The polyaniline-ferric oxide (Fe2O3) composites have been prepared for different weight percentage such as 5%, 10%, 15% and 20% of Fe2O3. The polymerization was carried out by in-situ chemical oxidation technique with ammonium persulphate (APS) as an oxidizing agent in aqueous sulphuric acid as dopent under constant stirring at 0-4 oC. The characterization of polymer composites has been carried out by FT-IR, UV-Vis so as to conform polymerization, XRD for elucidating the structure of composites. The morphology of composites was studied by SEM. Temperature dependent D.C. electrical conductivity measurement has been carried by four probe technique in the range of 303-373 K. It has been observed that conductivity of all composites is found to be increasing by increasing temperature. The composites of 5%(PF-1) and 10%(PF-2) has been found to be more while composites 15%(PF-3) and 20%(PF-4) has found to be lower than that of pure PANI over entire temperature range. The enhancement in conductivity of PF-1 and PF-2 composites may be due to uncoiling of polymeric chain due to strong interaction of PANI with Fe2O3 crystallites as suggested by FT-IR and XRD studies. Lowering in conductivity of PF-3 and PF-4 may be due to increasing the content in composition which gradually weakened interaction between PANI and Fe2O3; leads to free PANI Chain coexist in the composites and may be due to the particle blockage in conductive path by additive embedded in PANI matrix.

A new method for the synthesis of water soluble Polyaniline (PANi) using Hemin Chloride (H.C) in the presence of hydrogen peroxide (H.P) is presented. Hemin chloride is an effective catalyst for the oxidative polymerization of aniline in the presence of hydrogen peroxide at room temperature. The UV- Vis absorption spectra of the product show a distinct absorption peak at 430 nm in pH 4.0 buffer solution, indicating the formation of Polyaniline. A new mechanism for polymerization of aniline in the presence of H.0 and H.P is also presented.