Poly 3-methylthiophene Research Articles

Multi-functionality in de-doped poly 3-methylthiophene memristor device

Multi-functional devices are the recent trends in research, as they are cost-effective and reduce e-waste. In this study, detailed current-voltage measurement is performed on electro-polymerized Poly 3-methylthiophene (P3MT) thin film sandwiched between stainless steel (SS) and silver (Ag) electrodes, and the fabricated two-terminal device consisting of geometry SS/P3MT/Ag. Systematic and comparative measurements on partially doped P3MT devices with three dopants (TBAPF6, LiClO4 & TBABF4) helped in realizing multi-functionality. In all the devices the following multifunctional features are demonstrated: negative differential resistance (NDR), sweep voltage-controlled resistive switching, analog memory, and synaptic plasticity. Charge transport in all the devices is modeled based on charge accumulation, trapping, and de-trapping of injected carriers.

Poly(3-Methylthiophene)/Graphene Composite Cathode for Rechargeable Aluminum-Ion Batteries.

To reduce the dependence on traditional fossil energy, developing efficient energy storage systems is urgent. The reserves of aluminum resources in the earth's crust are extremely rich, which makes aluminum-ion batteries a promising competitor of new energy storage devices. Here, we report a poly(3-methylthiophene)/graphene (P3TH/Graphene) composite as the cathode of an aluminum-ion battery. The adjustment of polymer chain spacing by the methyl side chain provides a channel conducive to the transport of large-size AlCl4- complexes. The addition of electron donor groups also changes the electron delocalization characteristics of polymers and improves the specific capacity of the material. At the same time, the in situ composite of graphene can enhance the Π-Π interaction to form a favorable electronic transmission channel. At a current density of 200 mA g-1, the P3TH/Graphene composite showed a specific capacity of ∼150 mA g-1. The flexible structure of the polymer also guarantees the excellent rate capability of the composite.

PVDF/poly(3-methylthiophene)/MWCNT nanocomposites for EMI shielding in the microwave range

This work presents a new approach to enhance EMI shielding efficiency of nanocomposites of dielectric polymers, multiwalled carbon nanotubes (MWCNTs) and intrinsically conducting polymers for account of using core-shell morphology for conducting components. To realize this approach new ternary nanocomposites of poly(vinylidene fluoride) (PVDF), MWCNTs and poly(3-methylthiophene) doped by Cl− anions (P3MT) were prepared through synthesis of thermally stable core/shell nanocomposites PVDF/P3MT and MWCNT/P3MT. These binary nanocomposites were mixed with pure MWCNTs or PVDF followed by compression molding to prepare the ternary nanocomposites of different morphology to discriminate their EMI shielding properties in a wide frequency range (1–67 GHz). Values of the tangent of dielectric loss angle, the efficiency of transmission, reflection and absorption of microwave radiation, and shielding efficiency (SE) of the specified materials were found from analysis of spectral dependences of their complex dielectric constants. It was shown that while the melt mixing of the binary PVDF/P3MT nanocomposite with MWCNTs both in a pure state and in the binary nanocomposite (MWCNT/P3MT) expectedly strongly enhances SE of the former, this effect is non-linear and depends on presence/absence of the P3MT shell on the MWCNT core. The ternary nanocomposite PVDF/P3MT/MWCNT made of the binary polymer-polymer nanocomposite PVDF/P3MT and pure MWCNTs showed highest SE values at the frequencies above 4.5 GHz up to 68.4 dB at 67 GHz in the case of the 1 mm thickness sample. However, below 4.5 GHz the SE was higher in the case of the ternary nanocomposites containing core/shell MWCNT/P3MT nanocomposite instead of pure MWCNT.

PROPERTIES OF NANOSTRUCTURED COMPOSITES OF POLY(VINYLIDENE FLUORIDE) WITH DOPED POLY(3-METHYLTHIOPHENE)

The combination of properties of intrinsically conducting polymers (ICPs) and functional nanostructured template materials opens up prospects for their use in various fields, ranging from bioelectronics to sensors and energy conversion. Successful combinations solve one of the important drawbacks of many ICPs, created by their insolubility and infusibility, and help to achieve their full potential in thermally processable materials. When developing such hybrid materials, it is necessary to take into account the sensitivity of ICP properties to interphase interactions due to extended π-conjugation in these polymers. However, this aspect of ICP-based nanocomposites has not been sufficiently studied yet. In this paper we investigate the effect of template submicron poly(vinylidene fluoride) (PVDF) particles and the nature of the dopant on properties of poly(3-methylthiophene) (P3MT) precipitated as the shell at the PVDF core surface in the course of the 3MT oxidative polymerization. For this purpose, we compare the properties of P3MT phase of the composites with the properties of the neat P3MT doped with dodecylbenzenesulfonate (DBS), perfluorooctanoate (PFO) and chloride anions. In the formed composite core-shell particles the P3MT is in the form of asymmetric nanoparticles which are localized almost exclusively at the surface of PVDF particles. According to the conjugation length, neat polymers form the following series: P3MT-Cl > P3MT-DBS > P3MT-PFO as evidenced by the IR spectral analysis. In their composites the conjugation length of P3MT doped with Cl- does not change noticeably, while for the DBS and PFO anions cases it increases and for the DBS case it exceeds that of Cl- case. X-ray phase analysis showed an increase in the degree of crystallinity of P3MT-Cl and P3MT-DBS phases in the composition of composites by 1.4 and 1.3 times relative to the corresponding values for the neat doped P3MTs. Such an increase can be caused by the influence of the local electric field of the dipoles of the electroactive part of the crystalline phase of PVDF (β- and γ-phase) on the spatial arrangement of charged P3MT macromolecules formed on the surface of PVDF. Thermogravimetric studies show an increase in the thermal stability of the doped P3MT phase of nanocomposites while conductivity measurements reveal a significant effect of the nature of the dopant anion.

Effect of synthesis temperature on the charge transport properties of poly(3-methylthiophene) devices

Low temperature-dependent I-V measurement was adopted to investigate an insight into the effect of synthesis temperature on the field and temperature-dependent charge transport properties of electrochemically polymerized poly(3-methylthiophene) devices. Devices having different doping levels were fabricated at two different temperatures, one at room temperature (25oC) and another at a lower temperature (5oC). The transport mechanism in the devices were studied in the temperature range 40 K to 300 K. Our studies revealed that trap controlled space charge limited conduction (TCSCLC) mechanism dominated the transport mechanism at higher temperature(T>200K) and changed to field dependent mobility model at lower temperature(T<200K). It was observed that the synthesis temperature influenced the transport parameters. Devices prepared at low temperature showed an increase in resistivity and a corresponding decrease in the charge carrier mobility compared to those prepared at high temperature. Moreover, the distribution of the trap states in the devices was also affected by the synthesis temperature, with devices fabricated at low temperature exhibiting a wider trap state distribution.

Poly 3-methylthiophene based memristor device for neuromorphic computing

Von Neumann computing-based memory has reached its limit, it is incapable of performing two tasks simultaneously, i.e. data storage and computation. Artificial neuromorphic computing (ANC) inspired by biological neural network is the next generation memory technology, which is based on a memristor device. Study of memristor is a hot topic in electronic research as it exhibits multifunctionality. Electrochemically synthesized doped Poly 3-methylthiophene (P3MT) based single layer memristor device showcases neuromorphic computing applications when resistance is enhanced to insulating state, by the process of de-doping. Morphological/structural deformation created by the process of de-doping on the surface of active layer is responsible for multifunctionality such as controllable negative differential resistance (NDR), unipolar resistive-switching (RS), multi-level RS (analog memory) and bio-inspired artificial synapse in SS/P3MT/Ag device geometry.

Flexible Supercapacitors Based on Stretchable Conducting Polymer Electrodes.

Supercapacitors are widely used in various fields due to their high power density, fast charging and discharging speeds, and long service life. However, with the increasing demand for flexible electronics, integrated supercapacitors in devices are also facing more challenges, such as extensibility, bending stability, and operability. Despite many reports on stretchable supercapacitors, challenges still exist in their preparation process, which involves multiple steps. Therefore, we prepared stretchable conducting polymer electrodes by depositing thiophene and 3-methylthiophene on patterned 304 stainless steel (SS 304) through electropolymerization. The cycling stability of the prepared stretchable electrodes could be further improved by protecting them with poly(vinyl alcohol)/sulfuric acid (PVA/H2SO4) gel electrolyte. Specifically, the mechanical stability of the polythiophene (PTh) electrode was improved by 2.5%, and the stability of the poly(3-methylthiophene (P3MeT) electrode was improved by 7.0%. As a result, the assembled flexible supercapacitors maintained 93% of their stability even after 10,000 cycles of strain at 100%, which indicates potential applications in flexible electronics.

Doped poly 3-methylthiophene device exhibits negative-differential resistance

Poly 3-methylthiophene (P3MT) polymer is electrochemically deposited on stainless steel substrate and a sandwich device structure (SS/P3MT/Ag) is realized by placing a top metal contact to fabricate a two-terminal device. The polymer is first doped with & dopants and then de-doped for 30 seconds. The current-voltage (I-V) measurement is carried out on a de-doped P3MT device to probe the charge-transport and negative-differential resistance (NDR). In the present experiment, NDR and Charge transport mechanism varies with the dopant. The magnitude of NDR, i.e., peak-valley current (PVCR) depends on the voltage swept and dopants. We propose the reason for anomaly NDR is dopant-induced trap-states.

A new voltammetric sensor for penicillin G using poly(3-methylthiophene)-citric acid modified glassy carbon electrode

In this study, an effective voltammetric sensor was developed for determination of penicillin G by electropolymerization of 3-methylthiophene with citric acid on glassy carbon electrode. Penicillin G selective electrode was prepared in water:acetonitrile (1:1) mixture containing 0.1 M sodium perchlorate as electrolyte medium with cyclic voltammetry. Then, the electrochemical behavior of penicillin G on poly(3-methylthiophene) based membrane modified electrode was investigated by cyclic voltammetry, differential pulse voltammetry and differential pulse stripping voltammetry techniques. When the penicillin G responses of the modified glassy carbon electrode were compared with the bare glassy carbon electrode responses, it was seen that the selectivity and sensitivity of the penicillin G responses of the modified electrode significantly increased. A linear calibration graph for penicillin G was obtained in the concentration range of 0.07 to 4.0 mM with the prepared electrode. The R2 value was calculated as 0.9999 from the linear calibration curve. The limit of detection and limit of quantitation of the poly(3-methylthiophene)-citric acid modified glassy carbon electrode for penicillin G were calculated as 8 μM and 28 μM, respectively. In addition, the developed electrode for the detection of PeG was applied to milk samples. The recovery efficiency of the poly(3-methylthiophene)-citric acid modified glassy carbon electrode was obtained in the range of 93 % and 103 % for three different milk samples. As a result; the modified electrode can be used for residue penicillin detection in food and biological samples.

Effects on the emission of different interfaces formed between poly(3-methylthiophene) and poly(3-octylthiophene): electrochemical impedance and photoluminescence spectroscopy studies

With the aim of verifying the optical properties of the systems formed by poly(3-methylthiophene) (P3MT) and poly(3-octylthiophene) (P3OT) on platinum (Pt) for use in organic photovoltaic device applications, electrochemical preparations of different interfaces with poly(3-alkylthiophenes) (P3ATs), synthesized both with 18 °C and without temperature control, were compared. These interfaces were prepared both as blends (Pt/P3MT:P3OT) and as layered films (Pt/P3MT/P3OT and Pt/P3OT/P3MT). Electrochemical impedance spectroscopy (EIS) was used to characterize the systems, and based on Bode-Phase diagrams, it was possible to monitor the stabilization of radical cation and dication segments of the thiophene ring. The findings corroborated previous studies by electrochemical spectroscopy and using in situ Raman spectroscopy under the same experimental conditions. We were able to verify the effects of experimental variables, such as synthesis temperature and different kinds of deposition. Temperature was found to be an extremely important factor in synthesis, since films synthesized at 18 °C favored the stabilization of radical cation segments in the polymer matrix, and layered deposition also favored the stabilization of these segments, since the layer closest to the electrode can act as an induction layer for the stability of radical cation segments in the system. Photoluminescence spectroscopy was used to verify the optical properties of the interfaces, in which occur the contributions of three segments in the P3ATs matrix. Thus, it has been demonstrated through photoluminescence decay time that the relative amount of radical cation and dication segments in the polymer matrix affects the lifetime of these segments in the different materials prepared, due to emission effects for these systems.

Fabrication of poly(3-methylthiophene)/poly(ethylene oxide)/ruthenium oxide composite electrospun nanofibers for supercapacitor application

Fabrication of poly(3-methylthiophene)/poly(ethylene oxide)/ruthenium oxide composite electrospun nanofibers for supercapacitor application

Variation in Capacitive Performance of Poly(3-methylthiophene) Nanosheet Electrodes with Liquid/Semi-Solid/Solid Electrolytes

Variation in Capacitive Performance of Poly(3-methylthiophene) Nanosheet Electrodes with Liquid/Semi-Solid/Solid Electrolytes

Poly(3-methylthiophene)/Tungsten oxide hybrid materials for highly efficient electrochromic devices

Enhanced electrochemical and optical properties of poly(3-methylthiophene)/tungsten oxide (PMeT/WO3) hybrid nanostructure based electrochromic devices (ECDs) are presented. Hybrid nanostructures were prepared by electrodeposition technique in the presence of four different ionic liquids; 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (BMIMTFSI) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI). The electrochromic behaviors of the ECDs were investigated using cyclic voltammetry, chronoamperometry and transmittance measurements. PMeT/WO3/BMIMTFSI based ECD revealed excellent electrochromic properties of broad optical modulation (57.92%) and great coloration efficiency (398.32 cm2/C). Morphological structures of the thin films were examined by a scanning electron microscope (SEM), which showed that remarkable optical properties of PMeT/WO3 hybrid synthesized in BMIMTFSI medium can be attributed to the spongy network structure. The improved performance of the PMeT/WO3 hybrid electrodes and the facile synthesis through electrodeposition method demonstrate a viable strategy for preparing fast assembling high-performance hybrid electrodes for a wide variety of electrochemical devices.

Molecularly Imprinted Polymers as Solid-Phase Microextraction Fibers for the Isolation of Selected Antibiotics from Human Plasma.

The aim of this study was to examine the synthesis of novel molecularly imprinted polymer (MIP)-coated polythiophene and poly(3-methylthiophene) solid-phase microextraction fibers using the direct electropolymerization method. Synthesized SPME fibers were characterized with the use of various physicochemical instrumental techniques. MIP-SPME coatings were successfully applied to carry out the selective extraction of selected antibiotic drugs (amoxicillin, cefotaxime, metronidazole) and their metabolites (amoxycilloic acid, amoxicillin diketopiperazine, desacetyl cefotaxime, 3-desacetyl cefotaxime lactone, hydroxymetronidazole). Solid-phase microextraction parameters for the simultaneous determination and identification of target compounds were optimized using the central composite design (CCD), and they accounted for 5–15 min for desorption time, 3–10 for the pH of the desorption solvent, and 30–100 μL for the volume of the desorption solvent. High-performance liquid chromatography and mass spectrometry (MS) detectors such as quadrupole time-of-flight (Q-TOF MS) and triple quadrupole (QqQ MS) were applied to determine and to identify selected antibiotic drugs and their metabolites. The MIP-coated SPME are suitable for the selective extraction of target compounds in biological samples from patients in intensive care units.

Nano-, helical conducting poly(3-methylthiophene) prepared by one-step electro-deposition using cholesteric liquid crystal and anodic aluminum oxide as dual templates

Due to the importance of nano-, helical conducting polymers in both fundamental studies and applied research, poly(3-methylthiophene) (P3MT) with a nanosized helical structure was synthesized herein by using cholesteric liquid crystal (CLC) and an anodic aluminum oxide (AAO) film as dual templates. The monomer 3-methylthiophene was polymerised and filled into the nanopores of AAO in the CLC medium by a one-step electro-deposition method. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and circular dichroism (CD) analyses proved that the nano-, helical structure of P3MT was successfully obtained by this method. Polarized optical microscopy (POM) revealed that P3MT had the same texture as the CLC, which originated from the template effect of CLC. The electrochemical dual template-assisted approach is easily controlled, highly efficient, and inexpensive for fabricating nano-, helical conducting polymers.

Initiation and Polymer Density of Conjugated Polymer Brushes.

The growth mechanism and polymer density in conjugated polymer brush (CPB) films composed of poly(3-methylthiophene) (P3MT) are characterized. X-ray photoelectron spectroscopy experiments show that the initiation of aryl halide monolayers by Pd(PtBu3)2 produces disproportionated monolayer initiators. Unlike disproportionated species formed during the solution-phase initiation of aryl halides, which cannot mediate polymerization, the surface-bound initiators catalyze polymerization to form CPB films with a high grafting density (1.2 nm-2). Rutherford backscattering spectrometry (RBS) experiments show that P3MT CPB films have a characteristic monomer volume density (3.7 nm-3) that is indistinguishable from the volume density of spuncast poly(3-hexylthiophene) films. Using these RBS and XPS results, characteristics of P3MT CPB growth are obtained, including the turnover frequency (7.5 h-1) and polymer molecular weight (300 g/mol·nm).

Multi-color poly(3-methylthiophene) films prepared by a novel pre-nucleation electrodeposition grown method for enhancing electrochromic stability

Poly(3-methylthiophene) (PMeT) is considered a promising conductive polymer for applications in electrochromic displays due to its red to blue multi-color switch as well as low cost. However, the non-uniformity of the films caused by high electrochemical polymerization potentials during electrodeposition and the rapid electrochemical stability decay caused by weak adhesion limits its practical application. In this study, a new pre-nucleation electrodeposition method is developed to synthesize PMeT film. The nucleation grown progress is investigated by electrochemical fitting tests and scanning electron microscopy. Compared with a directly grown film, the pre-nucleation PMeT film presents excellent electrochromic EC transmittance modulation of 75% at wavelength of 1050nm, and sustains a transmittance modulation of about 91 % after 400 cycles. This was the result of enhanced uniformity and adhesion from the pre-nucleation method. The surface uniformity and roughness of PMeT films were analyzed by optical microscopy and atomic force microscopy measurements. After controlling thickness using this method, the PMeT films exhibited multiple transmittance change and red–green–blue color change.

Studies of electrochromic behavior of conducting copolymer of 3-methylthiophene with 3, 4-ethylenedioxythiophene

Co-polymer of poly (3-methylthiophene -co- 3, 4-ethylenedioxythiophene) (PMT-co-EDOT) can be synthesized by electrochemical method using the basic monomers such as acetonitrile/tertiary butyl ammonium perchlorate medium. The electrosynthesized co-polymer was characterized like FT-IR, UV–visible, XRD, SEM-EDS analysis and AFM technique. The spectroelectro electrochromic properties of the co-polymer were characterized through UV-transmittance spectra coupled with cyclic voltammetry (CV). From the spectro electrochemical measurement, the coloration efficiency was 685 cm2/C and the optical contrast (Δ%T) was 84 at the wavelength of 420 nm were calculated. The polymer films were displayed multicolour electrochromism. This co-polymer system is applicable as electrochromic devices.

Photoluminescent Response of Poly(3-methylthiophene)-DNA Single Nanowire Correlating to Nucleotide-Mismatch Locus in DNA-DNA Hybridization.

π-Conjugated polymers have become qualified candidates for biosensing owing to their unique optoelectronic properties and excellent biocompatibility. In this contribution, nucleotidemismatches in DNA hybridization, being variable in position, are reflected in a stark manner by poly(3-methylthiophene) (P3MT) nanowires (NWs), in which probe DNA sequence is properly functionalized. Selected as the systematic investigation are complementary target DNA (tDNA), random sequence DNA, and three kinds of 1-mer mismatched tDNAs with different mismatch loci away from the NW's surface. Nanoscale optical observation of the single P3MT NWs in solid states reveals that the more distant the mismatch position is from the surface, the higher the photoluminescence (PL) occurs, while the complementary sequence yields the highest but the random one remains the lowest. Hence, the PL intensity increases with the relative length of the DNA-DNA hybridization from the surface. These results deliver a new basis that π-conjugated polymers can be potentially applicable to detailed nucleotide analyses as in single nucleotide polymorphism.

Anomalous current–voltage and impedance behaviour in doped Poly 3-methylthiophene devices

Current–voltage (I–V) and impedance measurements are performed on electrochemically-doped poly(3-methylthiophene) (P3MeT) devices in metal/polymer/metal sandwich geometry. The detailed investigation shows the presence of negative differential resistance (NDR) in the sandwich devices with different metals in action as substrate and top electrode. It is found that the reiteration of I–V measurements significantly enhances the NDR. The P3MeT devices shows a considerable switching behaviour with ON to OFF ratio varying between two to three order but lacks the consistency in bias stress test. An anomalous behaviour in the impedance measurements in the form of a prolonged tail is observed in Cole–Cole plots towards lower frequency region, which gets more prominent with applied bias. This impedance anomaly is explained in terms of large distribution of relaxation times arising due to long lived trap states at the bulk and interface which is correlated with the NDR observed in P3MeT devices.