PEDOT Research Articles

Assessing the anomalous superdiffusive heat transport in a single one-dimensional PEDOT chain

We present a computational investigation on heat transport in a single polymer chain of poly-3,4-ethylenedioxythiophene (PEDOT). By applying equilibrium and nonequilibrium molecular dynamics simulations to evaluate the thermal conductivity, as well as by investigating how the polymer chain approaches equilibrium upon a local thermal excitation, we provide a robust picture assessing the anomalous superdiffusive (i.e., intermediate between ballistic and diffusive) character of its thermal transport. This assessment is provided by the present simulations showing that three scaling laws with unlike physical meaning and characterizing the thermal energy transport in one-dimensional systems indeed occur in the very same polymer chain with consistent critical exponents. In order to disentangle the effect of dimensionality, we perform a systematic comparison of transport features for a single one-dimensional (1D) PEDOT chain and a three-dimensional (3D) PEDOT crystal. Present simulations suggest that by increasing the dimensionality, the anomalous regime is completely removed as due to the occurrence of strong interchains anharmonic interactions. Finally, we prove that thermal transport in isolated single PEDOT chains belongs to a novel universality class of superdiffusion characterized by a critical exponent $\ensuremath{\beta}=1/2$.

Graphene with Fe and S Coordinated Active Centers: An Active Competitor for the Fe–N–C Active Center for Oxygen Reduction Reaction in Acidic and Basic pH Conditions

Proton exchange membrane fuel cells (PEMFCs) and metal–air batteries are gaining enormous attention due to their capability to fulfill the energy demand of the ever increasing population. Because the major bottleneck in the forward path of commercialization of such systems is mainly caused by the precious metal catalysts, there has been a paradigm shift in the development of Pt-free electrocatalysts to make the PEMFC systems cost competitive. Here, we report a Pt-free, iron and sulfur-doped, scrolled graphene (P12-900) prepared via annealing of polyethylenedioxythiophene (PEDOT) as a potential oxygen reduction electrocatalyst which could perform exceptionally well under acidic and basic electrolyte conditions. The residual iron chloride retained by the polymer matrix, which was employed as the oxidizing agent for the polymerization reaction, plays a vital role in generating the potential oxygen reduction reaction (ORR) active sites based on the iron and sulfur-doped graphene in the system. The composition...

Polydopamine-functionalized graphene nanoplatelet smart conducting electrode for bio-sensing applications

The development of a novel polydopamine (PDA)-functionalized graphene nanoplatelets (GNPs)-based disposable sensor is described. The sensor was fabricated by drop-coating PDA@GNPs in polyethylene glycol (PEG) and poly(3,4-ethylenedioxythiophene (PEDOT):poly(styrenesulfonate) (PSS) aqueous suspension onto the working area of a screen-printed electrode (SPE). The final sensor, designated as PDA@GNPs/PPP/SPE, was characterized by scanning electron microscopy (SEM), Raman spectroscopy, Faradaic electrochemical impedance spectroscopy (FEIS) and cyclic voltammetry (CV). Mediated detection of hydrogen peroxide (H2O2) via the redox properties of PDA was achieved. It showed excellent selectivity and sensitivity towards H2O2 with a limit of detection and sensitivity of 0.55 µM (S/N = 3) and 3.0 µA mM−1 cm−2, respectively. Thereafter, glucose oxidase (GOx) was immobilized onto the electrode to develop GOx/PDA@GNPs/PPP/SPE sensor. The glucose biosensor exhibited a limit of detection of 0.25 μM (S/N = 3) and a sensitivity of 0.51 μA μM−1 cm−2; thus, proving its potential suitability for bio-sensing applications.

Understanding the Impact of Film Disorder and Local Surface Potential in Ultraviolet Photoelectron Spectroscopy of PEDOT.

The spectra of conducting polymers obtained using ultraviolet photoelectron spectroscopy (UPS) exhibit a typical broadening of the tail σUPS ≈ 1 eV, which by an order of magnitude exceeds a commonly accepted value of the broadening of the tail of the density of states σDOS ≈ 0.1 eV obtained using transport measurements. In this work, an origin of this anomalous broadening of the tail of the UPS spectra in a doped conducting polymer, PEDOT (poly(3,4-ethylenedioxythiophene)), is discussed. Based on the semiempirical approach and using a realistic morphological model, the density of valence states in PEDOT doped with molecular counterions is computed. It is shown that due to a disordered character of the material with randomly distributed counterions, the localized charge carriers in PEDOT crystallites experience spatially varying electrostatic potential. This leads to spatially varying local vacuum levels and binding energies. Taking this variation into account the UPS spectrum is obtained with the broadening of the tail comparable to the experimentally observed one. The results imply that the observed broadening of the tail of the UPS spectra in PEDOT provides information about a disordered spatially varying potential in the material rather than the broadening of the DOS itself.

Scaling Effects on the Electrochemical Performance of poly(3,4‐ethylenedioxythiophene (PEDOT), Au, and Pt for Electrocorticography Recording

AbstractReduced contact size would permit higher resolution cortical recordings, but the effects of diameter on crucial recording and stimulation properties are poorly understood. Here, the first systematic study of scaling effects on the electrochemical properties of metallic Pt and Au and organic poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) electrodes is presented. PEDOT:PSS exhibits better faradaic charge transfer and capacitive charge coupling than metal electrodes, and these characteristics lead to improved electrochemical performance and reduced noise at smaller electrode diameters. PEDOT:PSS coating reduces the impedances of metallic electrodes by up to 18x for diameters <200 µm, but has no effect for millimeter scale contacts due to the dominance of series resistances. Therefore, the performance gains are especially significant at smaller diameters and lower frequencies essential for recording cognitive and pathological activities. Additionally, the overall reduced noise of the PEDOT:PSS electrodes enables a lower noise floor for recording action potentials. These results permit quantitative optimization of contact material and diameter for different electrocorticography applications.

Polyoxometalate Heterogeneous Nanostructures As Cathodes for Mg2+ Ion Storage

As global energy demands continue to rise each year, current state-of-the-art Li-ion battery (LIB) systems are predicted to reach the limit in the amount of energy that they can supply. In addition to this, LIBs are also limited by the low resource availability of Li metal. One proposed solution is to move away from LIBs to multivalent ion systems; of these alternatives, magnesium (Mg) is considered a promising material for the next generation of rechargeable batteries. Unlike Li, Mg metal does not form dendritic structures during cycling which would allow it to be employed as an anode which has a specific capacity of 2205 mAh/g compared to 777 mAh/g of the graphite anode that is currently used in LIBs. Mg also has a very high elemental abundance in the earth’s crust (2.44x104 ppm) which would drive down the production cost while simultaneously ensuring the longevity of these batteries in terms resource availability. Most importantly, the divalent nature of the Mg-ion means that it can carry twice the amount of charge per ion compared to Li. This is largely related to the high volumetric capacity (3833 mAh/ml) of Mg which is superior to even that of Li metal. While there is potential for Mg to replace LIBs, commercialization of these batteries has been hindered by sluggish insertion kinetics into cathode host materials as a direct result of the strong coulombic interactions experienced by the divalent Mg-ion. Due to this drawback, conventional metal oxide or sulfide insertion cathodes for Mg batteries tend to exhibit low capacities and operating voltages. In response to this, a large portion of Mg battery research is currently focused on the development of novel materials capable of functioning as cathodes for fast and efficient Mg-ion insertion. The idea proposed in this work is to depart from the conventional intercalation mechanism of LIBs and move towards a molecular cluster battery (MCB) based on polyoxometalate (POM) metal oxygen cluster molecules of early transition metals (Mo, W, V, or Nb). The unique redox activity of POMs are due to their intrinsic ability to form highly stable reduced and oxidized species allowing them to partake in fast reversible electron transfer reactions. Although POMs are also able to function as electron reservoirs, POMs themselves have negligible electronic conductivity as well as high solubility in both aqueous and organic media. Therefore, in order for these materials to be used as electrodes for electrochemical energy storage, they must first undergo hybridization with highly conductive insoluble substrates such as conductive organic polymers (COPs) or multi-walled carbon nanotubes (MWCNTs). The fabrication of heterogenous cathodes provide a “wiring” effect by electrically connecting the POM molecules allowing them all to take part in the redox chemistry while simultaneously anchoring them to a substrate, thus preventing any loss of active material to electrolyte dissolution during cycling. By taking advantage of the synergistic effect of pairing the ionically conductive POM molecule with the electrically conductive substrate; the resulting cathode material will thus be capable of fast electron transfer reactions with high ionic mobility. In this work, hybrid nanostructured electrodes of poly-3,4-ethylenedioxythiophene (PEDOT) and a phosphomolybdic acid (H3PMo12O40) POM have been fabricated electrochemically and applied as cathodes for Mg-ion storage. Preliminary cyclic voltammetry and galvanostatic cycling data have demonstrated an enhancement in the capacity of the PEDOT cathode after integration of the POM molecules throughout the polymer matrix. The initial cycling studies have also shown that the PEDOT-POM redox peaks are still present after 7 days of soaking in the organic electrolyte which suggests that the POM molecules do not readily dissolve out of the PEDOT matrix. This work highlights the potential of redox active POM inorganic clusters to function as cathodes with the capability of advancing the current state of Mg batteries.

Preparation of High Charge Storage Capacity PEDOT/Functionalized MWCNTs Hybrid Nanocomposite for Neural Electrode Applications

This paper presents the experimental methodology of identifying the most suitable Poly 3,4-Ethylene Dioxy Thiophene (PEDOT) based hybrid nanocomposite for neural electrode applications. The key requirement for such electrodes is high charge storage capacity, which enables generation of activation potential without crossing pain threshold. Nanomaterials are key enablers for this high charge storage capacity. Hence hybrid nanocomposites of PEDOT doped with a wide range of nanomaterials such as multi walled carbon nanotubes (MWCNTs), graphene nano platelets (GNPs) graphene oxide (GO), functionalized multi walled carbon nanotubes (FMWCNTs) were prepared and characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicate that the prepared PEDOT/FMWCNTs nanocomposite has highest charge storage capacity and very low interface impedance and thus is the most suitable material for neural electrode applications.

Electrochemistry of White Wine Polyphenols Using PEDOT Modified Electrodes

The conducting polymer PEDOT (poly-3,4-ethylenedioxythiophene) has been polymerized onto 3 mm and 10 µm electrodes from a propylene carbonate solution. The electrodes have then been tested in a Chardonnay wine, including dilutions in a model wine solution, with comparisons made to scans with a glassy carbon electrode. A well-defined oxidation peak was obtained for the white wine at PEDOT in the 400 to 450 mV (Ag/AgCl) range, where peaks were also obtained for the representative phenolics caffeic acid and catechin. The voltammetry at PEDOT was typical of a surface-confined process. Significant preconcentration, leading to an increased current response, was noted over a period of 20 min of holding time. Extensive PEDOT growth was observed in the microelectrode case, leading to current densities for the oxidation of caffeic acid over 1000 times greater than those observed at the macroelectrode, matching the high surface area and fractal-type growth observed in SEM images.

Preparation of High Charge Storage Capacity PEDOT/Functionalized Mwcnts Hybrid Nanocomposite for Neural Electrode Applications

There is an ever growing demand for the development of high charge storage capacity, biocompatible microelectrodes, which are essential for neural recording and stimulation applications. The challenge here is to increase the charge storage capacity. Higher charge density would enable to pump in higher charge at the electrode/biological element interface even in with a smaller area electrode. However, there is a tradeoff between electrode dimension and interface impedance. A decrease in the electrode dimension results in low capacitance and high impedance which is a major drawback for stimulation because higher signal amplitudes are required for efficiently stimulating the cells. In order to overcome this bottleneck, it is imperative to develop materials having higher active area for the same geometric area. This not only reduces the interface impedance but also increases the specific capacitance. In developing these materials, biocompatibility and long term stability considerations must be taken into consideration. Biocompatible conducting polymers are good candidates for these applications and are being utilized as electrode materials in neuro prosthesis research for the past two decades. Yet the quest of high charge density electrode is still unmet. Among them, PEDOT (Poly Ethylene Dioxy Thiophene) is considered to be one of the promising conducting polymers due to its excellent electronic and ionic conductivity which cater low impedance and high specific capacitance, ease of fabrication by electro chemical polymerization along with excellent biocompatibility and bio stability. But PEDOT suffers from low cycling stability due to its low mechanical strength leading to decrease in pseudo capacitance and conductivity. Choosing the right dopant in PEDOT could potentially overcome these issues. In this work, we have synthesized different hybrid nanocomposites of PEDOT by doping different types carbon based 2D nanomaterials. The syntheses of these nanocomposites were carried out using electro polymerization. The electrode deposition was carried out using Chrono Amperometry, a widely used Potentiostatic technique. The idea behind using these 2D nanomaterials is well explored owing to the inherent advantages of these materials such as extraordinary mechanical strength, electrical conductivity and high chemical stability. Furthermore, the high surface to volume ratio results in higher surface charge, thereby resulting in a higher storage capacity. The focus of this endeavor is to study the charge storage capacity of the synthesized hybrid nanocomposites. The dopants that were used to synthesize the nano composites were Graphene nano platelets, Graphene Oxide, Multiwalled Carbon Nanotubes (MWCNTs) and functionalized MWCNTs. Similar conditions were adapted for electro polymerization. All the experiments were carried out at a scan rate of 100 mV/s using CH Instruments electro chemical setup shown in Fig.1. These include finite pulse potential amplitude of 1V and 120s pulse duration. Amongst all the materials, functionalized MWCNTs demonstrated the highest charge storage capacity as can be inferred by the cyclic voltammograms shown in Fig. 2(a). Functionalized CNTs not only disperse well in the precursor solution but also get embedded in a greater quantity in PEDOT matrix owing to their inherent negative charge. After identifying the right choice of dopant, the next step is to optimize the electro polymerization conditions so as to enhance the charge storage capacity to the best possible value. Cyclic voltammograms (CV) of PEDOT/Functionalized MWCNTs (PEDOT/FCNTs) as shown in Fig. 2(b) reveals that the area of the CV curve is highest for a loading percentage (wt/vol) of 1 mg/ml compared to other loading percentages. We observed that beyond 1 mg/ml, the excess concentration of MWCNTs is impeding the electro polymerization and is not resulting in a good film. The loading was fixed to 1 mg/ml for subsequent experiments. The next parameter that was optimized is the potential of electro polymerization with the duration of electro polymerization being 800s. As can be observed from Fig. 2(c), the suitable potential is 1 V. Voltages beyond this show a reduced charge storage and may be attributed to over oxidation during polymerization. Similarly, Fig. 2(d) reveals that area of the CV curve has attained maximum at pulse duration of 800s by keeping the amplitude as constant at 1V. Fig. 3 depicts the magnitude plot of electrode interface impedance for the PEDOT/CNT-COOH nanocomposite deposited at 1V with pulse duration of 800s in the frequency range of 0.1Hz to 1MHz. Hence, the best possible charge storage capacity and lowest interface impedance is obtained for a ratio of 1mg/ml (wt/vol) with electro polymerization amplitude of 1V and pulse duration 800s. Further morphological studies would be carried out in due of course of time to gain a deeper understanding in the synthesis of hybrid nanocomposite of PEDOT/FCNTs. Figure 1

Increase in electron scattering length in PEDOT:PSS by a triflic acid post-processing

A stringent limitation in many optoelectronic devices, such as solar cells and light emitting diodes, is the intrinsic need for a transparent electrode. Uniting relevant aspects, indium tin oxide (ITO) is often the material of choice, however, alternatives are sought and being in particular found in conductive polymers. In this work, we present a novel doping strategy to arrive at highly conducting polymeric material based on poly-3,4-ethylenedioxythiophene (PEDOT). Based on commercial high conductivity PEDOT:PSS (Clevios PH 1000), and a post processing with aqueous triflic acid delivers a material that is both transparent and of low resistivity (5.23 × 10−4 Ω cm). Furthermore, this material retains its conductive character over a large temperature range, indicating metallic behaviour. This is further supported by positive magnetoconductance effects at low temperatures (1.8–10 K) and extended mean free paths of the conduction electrons are observed—evidencing for a metallic state in this polymer.Graphical abstract

Polyethylenedioxythiophene and molybdenum disulfide nanocomposite electrodes for supercapacitor applications

An innovative nanocomposite electrode was chemically synthesized using molybdenum disulphide (MoS2)- polyethylenedioxythiophene (PEDOT) to understand the charge mechanism in a symmetric supercapacitor. The MoS2-PEDOT nanocomposite was produced at various ratios of MoS2 to ethylenedioxythiophene (EDOT) in an aqueous medium of polyanions polystyrene sulfonate (PSS) and cetyltrimethylammonium bromide (CTAB) at controlled conditions. The morphology, crystallinity, and optical properties of MoS2-PEDOT nanocomposite materials were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, particle size analyzer, Raman spectroscopy, X-ray-diffraction, and transmission electron microscopy (TEM) techniques, respectively. The electrochemical properties of the supercapacitor were investigated using cyclic voltammetry, charging–discharging at constant current and electrochemical impedance spectroscopy (EIS) techniques. The specific capacitance, power and energy densities of the supercapacitor were estimated using cyclic voltammetry (CV), charging–discharging, Nyquist and Bode plots. The specific capacitance was estimated to be 361 Farad/gram (F/g) for the 1:2 weight ratio of MoS2 to the EDOT monomer in the MoS2-PEDOT nanocomposite based electrodes. Nevertheless, this study provides a fundamental aspect of synthesis of nanocomposite material for optimum attainment supercapacitive properties based on the MoS2-PEDOT nanocomposite electrode for practical energy storage applications.

Polymer Sensitive Elements for Gas Sensors of Ammonia

The influence of ammonia on the optical absorption spectra of thin films of polyaniline (PANI), poly-3,4-ethylenedioxythiophene (PEDOT), mixtures thereof, and the bilayer film structures based on PANI and PEDOT obtained by electrochemical method were studied. The kinetics of changes in the optical absorption of these structures under the action of ammonia was explored in the spectral range of 350 ... 900 nm. We proved that the thin-film structure of PANI / PEDOT significantly extends the spectral range of sensitivity to ammonia of individual PANI n PEDOT films by superposition of high gas sensitivity of PANI and PEDOT films in the range of wavelength of 500 ... 700 nm and 350... 550 nm respectively. It was shown that the area under the spectra of change of the optical absorption of thin-film structure of PANI / PEDOT is in 1.45 times larger than the area of the same for individual components of the layers, which is the key to increasing the sensitivity of the gas sensors. The results can be used to optimize ammonia gas sensors for monitoring biotechnological processes in food industry and the environment.

Functional conductive nanomaterials via polymerisation in nano-channels: PEDOT in a MOF.

Reactions inside the pores of metal-organic frameworks (MOFs) offer potential for controlling polymer structures with regularity to sub-nanometre scales. We report a wet-chemistry route to poly-3,4-ethylenedioxythiophene (PEDOT)-MOF composites. After a two-step removal of the MOF template we obtain unique and stable macroscale structures of this conductive polymer with some nanoscale regularity.

Capacitance behaviors of EDOT and pyrrole copolymer, and equivalent circuit model

In this paper, a copolymer of 3,4-Ethylenedioxythiophene (EDOT) and pyrrole (Py) were electrochemically synthesised on glassy carbon electrode by cyclic voltammetry (CV). The modified electrodes were characterised by CV, Fourier transform infrared-Attenuated total reflectance, scanning electron microscopy, energy dispersion X-ray analysis, galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS) and stability measurements. Capacitor performances of polypyrrole (PPy), poly(3,4-ethylenedioxythiophene (PEDOT), and poly(3,4-ethylenedioxythiophene-co-pyrrole) (P(EDOT-co-Py)) films were comparatively studied in 0.5 M H2SO4 solution. In addition, the experimental and theoretical data of EIS were simulated by the equivalent circuit model of Rs(Cdl1(R1(QR2)))(Cdl2R3). The highest specific capacitances of PEDOT, PPy and P(EDOT-co-Py) films were obtained as Csp = 85, 63 and 89 mFcm−2, respectively. The highest double-layer capacitance and phase angle (θ) were obtained as Cdl = 0.43 mFcm−2 and θ = 73.1° for initial feed ratio of [EDOT]0/[Py]0 = 1/50, respectively. The capacitive results of copolymers are promising electrode materials for high-performance electrical energy storage devices.

Plastic Flexible Memory Chip Devices

A lines of advances in organic memory technology is demonstrated that enable an entirely new low-cost memory technology. Inventors incorporate these advances with the one of the most flexible material PLASTIC. This novel memory technology can be utilized in a 3D onetime-programmable storage array. Without the prohibitive costs of silicon processing, this memory is able of setting cost points several orders of magnitude lower than their inorganic counterparts. They have also progressively integrated this technology onto flexible plastic substrates. Combined with stacking, these vertical memory elements can create read only memory densities denser than many inorganic memories, at a fraction of the cost. A conducting plastic has the potential to put into a mega bit of data in a millimetre-square device-10 times denser than current magnetic memories. This system is cheapand fast, but cannot be rewritten, so would only be suitable for permanent storage. The system sandwiches a blob of a conducting polymer called PEDOT and a silicon diode between perpendicular connection. The key to the new technology was discovered by passing high current through PEDOT (Polyethylenedioxythiophene) which converts it into an insulator, rather like blowing a fuse .The polymer hastwo possible states conductor and insulator, that form the one and zero, necessary to put into digital data

Organic high-sensitive elements of gas sensors based on conducting polymer films

ABSTRACTThe influence of ammonia on the optical absorption spectra of thin films of polyaniline (PANI), poly-3,4-ethylenedioxythiophene (PEDOT), mixtures thereof, and the bilayer film structures based on PANI and PEDOT obtained by electrochemical method were studied. The kinetics of changes in the optical absorption of these structures under the action of ammonia was explored in the spectral range of 350 … 900 nm. It was shown that thin film bilayer structure PANI / PEDOT significantly broaden the range of spectral sensitivity to ammonia compared to individual films.

Lyotropic Supramolecular Polymer Systems with Anisotropic Functional Properties

SummaryWe have synthesized highly ordered nanostructured conducting PEDOT (poly (3,4ethylenedioxythiophene)) through chemical and electrochemical polymerization of bio based liquid crystalline templates and modified transducer used for the detection of ascorbic acid and nicotine.

GAS SENSORS BASED ON ORGANIC-INORGANIC NANOCOMPOSITES

The use of nanocrystals with large specific surface in sensor structures provides their high sensitivity to molecules of adsorbed gases. The aim of the work was to create sensor elements based on composite films of poly-3,4-ethylenedioxythiophene (PEDOT) in combination with nanocrystals of porous silicon (PS) and zinc oxide (ZnO) and to study the effect of adsorption of ammonia, ethanol and acetone molecules on the electrical parameters of the PEDOT-PS-ZnO structure.To produce film of PEDOT-PS-ZnO hybrid composite, 1% suspension of PEDO-PSS, zinc oxide with a particle size of 100 nm (Sigma-Aldrich Co, USA) and PS nanocrystals, obtained by electrochemical etching of silicon wafer were used. Research of adsorption-desorption processes in the composite films was carried out by measuring their electrical parameters at different concentrations of the analyzed gases. To evaluate the sensor properties, the adsorption sensitivity of the composite films was calculated and their dynamic characteristics were studied.Increase of electrical resistance of nanocomposite due to adsorption of ammonia, ethanol and acetone molecules was registered. The almost linear dependence of the resistance on the concentration of ammonia and acetone was observed. It is a significant advantage in developing of the gas sensors. The maximum sensitivity of the sensor elements is in the range of 1-2% concentration of the analyzed gases and the response time is 60-80 s. The films with higher content of PS nanocrystals were more sensitive to molecules of ammonia and ethanol, and the films containing more nanoparticles of ZnO - to molecules of acetone. To control functional parameters of the sensor films, the content ratio of semiconductor nanoparticles in hybrid composite can be changed.The combination of nanoparticles of porous silicon and zinc oxide provides not only an increase in working surface area of sensors, but also high sensitivity and selectivity to the ammonia, ethanol and acetone molecules. The obtained results can be used to create effective analyzers of gases.

Novel amperometric sensors for nitrite detection using electrodes modified with PEDOT prepared in ionic liquids

Novel amperometric sensors based on poly-3,4-ethylenedioxythiophene (PEDOT) were prepared and characterized for nitrite detection. An experimental matrix of two substrate materials (glassy carbon and gold) and four electrolytes used for preparation of electrodes (water, acetonitrile, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide) were investigated for the preparation of the sensors. The obtained films were characterized using scanning electron microscopy, cyclic voltammetry, amperometry, and electrochemical quartz crystal microbalance. Both glassy carbon and gold electrodes modified with PEDOT showed excellent electrocatalytic activity toward nitrite oxidation. An improved influence of the electrodes prepared in ionic liquids could be observed for the detection of nitrite, expressed by higher electrocatalytic activity and better sensitivities. The sensors showed good stability, while only weak interferences with selected cations, anions, and small biomolecules were detected.

Fabrication and characterization of conductive poly (3,4-ethylenedioxythiophene) doped with hyaluronic acid/poly (l-lactic acid) composite film for biomedical application

Poly 3,4-ethylenedioxythiophene (PEDOT), a polythiophene derivative, has been proved to be modified by chemical process as biocompatible conductive polymer for biomedical applications. In this study, novel hyaluronic acid (HA)-doped PEDOT nanoparticles were synthesized by the method of chemical oxidative polymerization, then conductive PEDOT-HA/poly(l-lactic acid) (PLLA) composite films were prepared. The physicochemical characteristics and biocompatibility of films were further investigated. FTIR, Raman and EDX analysis demonstrated that HA was successfully doped into PEDOT particles. Cyclic voltammograms indicated PEDOT-HA particles had favorable electrochemical stability. PEDOT-HA/PLLA films showed lower surface contact angle and faster degradation degree compared with PLLA films. Moreover, the cytotoxicity test of PEDOT-HA/PLLA films showed that neuron-like pheochromocytoma (PC12) cells adhered and spread well on the surface of PEDOT-HA/PLLA films and cell viability denoted by MTT assay had a significant increase. PEDOT-HA/PLLA films modified with laminin (LN) also exhibited an efficiently elongated cell morphology observed by fluorescent microscope and metallographic microscope. Furthermore, PEDOT-HA/PLLA films were subjected to different current intensity to elucidate the effect of electrical stimulation (ES) on neurite outgrowth of PC12 cells. ES (0.5mA, 2h) significantly promoted neurite outgrowth with an average value length of 122±5μm and enhanced the mRNA expression of growth-associated protein (GAP43) and synaptophysin (SYP) in PC12 cells when compared with other ES groups. These results suggest that PEDOT-HA/PLLA film combined with ES are conducive to cell growth and neurite outgrowth, indicating the conductive PEDOT-HA/PLLA film may be an attractive candidate with ES for enhancing nerve regeneration in nerve tissue engineering.