Conducting Polymer Materials Research Articles

Preparation method and properties of conductive silicone rubber

Carbon nano-conductive silicone rubber is a type of composite conductive polymer material. It has good electrical conductivity, thermal conductivity and high magnetic flux. It has a good application prospect to replace most traditional conductive materials. However, at present, its mechanical strength is poor, the strain is small, and its tensile strength is weak, which limits the application of carbon nano-conductive silicone rubber. For this reason, this paper uses carbon fiber as filler to prepare carbon-based nano-conductive silicone rubber by solution blending method, the preparation method analysis and performance research were carried out and the research results can provide a reference for the preparation of high-sensitivity, large-range flexible sensors.

High-Precision Thin Wall Bipolar Plates for Fuel Cell Applications via Injection Compression Molding with Dynamic Mold Temperature Control.

In recent years, the demand for polymer compound solutions for the application of bipolar plates in polymer electrolyte membrane fuel cells (PEMFC) has increased continuously due to significant cost and lifetime advantages compared to metallic solutions. The main challenge of the compounds is the high filler content required to ensure sufficient electrical conductivity of the bipolar plates. The associated increase in viscosity and simultaneously increased thermal conductivity limit the conventional injection molding process in terms of achievable flow path length to wall thickness ratios (plate aspect ratio). In order to evaluate the extent to which highly modified electrically conductive polymer material systems can be processed into thin-walled and highly dimensionally stable bipolar plates, an injection compression molding process with dynamic mold temperature control (ICM-DT) has been developed. For this purpose, a compound was prepared from polypropylene (PP) and graphite-flakes. The compound was characterized with respect to the achieved filler content, the electrical conductivity, as well as the pressure- and temperature-dependent solidification range. The ICM-DT experiments were carried out by varying the maximum mold temperature and the compression force. In addition, the process was designed with multiple compression and decompression steps to account for a possible pressure-dependent solidification of the compound. The plates were characterized with respect to the achieved plate aspect ratio and the flow-path-dependent dimensional thickness stability. It was shown that the plate aspect ratio could be increased by up to 125% with the maximum filler content compared to conventional injection molding processes provided in the literature. With the multi-stage ICM-DT process, it was also possible to optimize the thickness dimensional stability with a maximum deviation of 3% over the flow path.

Improved Interfacial Contact Using Surface Modified Lithium Metal Powder in All-Solid-State-Lithium-Sulfur-Batteries

All-Solid-State-Lithium-Sulfur-Batteries(ASSLSBs) are the most promising candidate for next generation secondary battery because of its high theoretical specific capacity of Lithium metal (3860 mAhg-1) and elemental sulphur (1672 mAhg-1). However, the shuttle effect of Li-S battery is the major obstacles of commercialization. And there are still remaining safety issues due to dendrite formation during lithium deposition. Adopting solid state electrolyte can be a solution to these issues. Recent studies of all-solid-state-batteries have achieved high capacity and good stability. But there are still hindrances of interface problems between solid electrolyte and active materials. The interfacial issues of solid electrolytes can be solved by applying lithium metal powder. In this study, we fabricate composite electrode which have large specific contact area as well as intimate contact of electrode component by using solid electrolyte and lithium metal powder. Surface of lithium metal powder is modified by an ion conductive polymer material to prevent side reaction of solid electrolyte and lithium metal powder. This study can provide a new way of producing the surface modified lithium powder as an anode material for All-Solid-State-Lithium-Sulfur-Batteries.

Hybrid composite based on conducting polymers and plasmonic nanomaterials applied to catalysis and sensing

Combining plasmonic and semiconductors offers significant potential in creating sensing and photocatalytic devices. Nanocomposites including both metals and semiconductors can control the charge states in the metals that can enhance catalysis activity along with plasmon-enhanced spectroscopy. Here we demonstrate the use of conducting polymer materials with plasmonic nanomaterials to boost up to five-fold plasmon-enhanced Raman scattering spectroscopy signal strength and support oxidation of target molecules through supporting charge transfer processes. This work demonstrates the use of conducting polymers as a semiconductor platform to support plasmonic catalysis and sensing.

Conducting polymeric nanocomposites: A review in solar fuel applications

Over the last few decades, research is being carried out in the field of photocatalysis to investigate for fuels production in sustainable manner. Due to an energy depletion and CO2 emission in the current situation urge us to produce alternative fuels. Water splitting and the reduction of carbon dioxide using various photocatalysts are being developed as promising sustainable methods to obtain eco-friendly energy sources. Conducting polymers (CP) stand out among the current pool of studied photocatalysts due to their high light absorption efficiency, good stability, tunable electronic characteristics, and cost effectiveness. Various CP, such as polyaniline, polythiophene, and polypyrrole have been integrated with different semiconducting nanomaterials to produce photocatalytic composites. Therefore, in this review, we focus on the synthesis of CP and their nanocomposites for application in CO2 photoreduction and water splitting into fuel production using different polymeric composites. Many composite photocatalysts show synergistic effects between the polymeric material and other counterparts in the composite. The improvement in the inactivity of the composite can be attributed to the band configurations of the composite. Improving the separation of excitons, widening the light absorption region, enhancing the substrate adsorption, and preventing photocorrosion conductive polymers can significantly increase the photocatalytic activity under visible light. The addition of conducting polymers with an inorganic materials dramatically change their band positions and may reduce the possiblilty of electron hole recombination. Here, we explain by what means conductive polymeric material can improve the efficiency of the composite in an organized manner, thereby providing a comprehensive reference to the field. Finally, the current challenges and future perspectives of polymeric catalysts have been discussed briefly.

Wearable Sensor Based on Flexible Sinusoidal Antenna for Strain Sensing Applications.

A flexible sinusoidal-shaped antenna sensor is introduced in this work, which is a modified half-wave dipole that can be used for strain sensing applications. The presented antenna is an improved extension of the previously introduced antenna sensor for respiration monitoring. The electrical and radiative characteristics of the sinusoidal antenna and the effects of the geometrical factors are studied. An approach is provided for designing the antenna, and equations are introduced to estimate the geometrical parameters based on desired electrical specifications. It is shown that the antenna sensor can be designed to have up to 5.5 times more sensitivity compared to the last generation of the antenna sensor previously introduced for respiration monitoring. The conductive polymer material used to fabricate the new antenna makes it more flexible and durable compared to the previous generation of antenna sensors made of glass-based material. Finally, a reference antenna made of copper and an antenna sensor made of the conductive polymer are fabricated, and their electrical characteristics are analyzed in free space and over the body.

Nanoparticles improving polyaniline electrical conductivity: A meta-analysis study

Polyaniline is a conductive polymer that attracts the attention of many researchers around the world. The history of this polymer begins in 1862 when Letheby first reported this material. Since then, a myriad of studies has been conducted onthis material, and new works continue to investigate the potential of this material. Polyaniline has been improved with the help of Nanotechnology. The use of nanofillers has been seen as a quick and economical way to modify materials, drivinginnovations based on new physical and chemical properties from the conductive polymer materials and nanoparticles joining. Several works address the use of different nanoparticles, which leads to the practical impossibility of sifting through all this information. Thus, this work proposes to systematically collect data in the literature and investigate which nanoparticles can increase the electrical conductivity of Polyaniline (PAni). The results obtained demonstrate that among the possiblenanofillers, graphene and carbon nanotubes have great prominence. Furthermore, the results of the meta-analysis prove that PAni's conductivity increases when this polymer is modified with the aforementioned nanofillers.

Identification of the Model of Radiation Conductivity of Polymeric Materials

A technique for identifying a model of radiation conductivity of polymeric materials for chip packages of microelectronic equipment has been developed. On the basis of the developed technique, computer simulation of radiation charging of polymer cases of microelectronic equipment with increased conductivity was carried out. The research results are aimed at the development of composite polymeric materials for chip packages of microelectronic equipment with conductivity that ensures the absence of electrostatic discharges and makes it possible to significantly increase the life of spacecraft.

Strong-Acid-Catalyzed Formation of Crystalline LiNbO3 at Low Ambient Temperatures.

A crystalline LiNbO3 material was synthesized at 80 °C by an optimized sol-gel method using a double alkoxide alcoholic solution in the presence of hydrogen peroxide (H2O2) and strong acids. The same reaction in the presence of water or acetic acid resulted in amorphous powders with fewer impurities but which crystallized only at 450 °C and higher temperatures. The purity of the crystalline material obtained at 80 °C is strongly dependent on the Li/Nb molar ratio used for the reaction. It appears that the combination of strong acids with H2O2 in air generates perfect conditions for the synthesis of low-temperature crystalline lithium niobate oxide derivatives and can be extended to various other metal oxides. The developed synthetic method opens the potential for the coating of low-melting-point conductive polymer materials with LiNbO3 crystalline films.

Expandable Graphite as a Multifunctional Flame-Retarding Additive for Highly Filled Thermal Conductive Polymer Formulations.

Expandable graphite (EG) and graphite (G) were assessed as multifunctional additives improving both flame retardancy and thermal conductivity in highly filled, thermal conductive polymeric materials based on polyamide 6 (PA6). Fire testing was conducted using modern UL-94, LOI and cone calorimeter test setups. It is demonstrated that thermal conductivity can significantly influence the time to ignition, although offering little fire resistance once ignited even in highly filled systems. Thus, for PA6 formulations containing solely 70 wt.% G, the peak heat release rate (pHRR) measured in cone calorimeter tests was 193 kW/m², whereas PA6 formulations containing 20 wt.% EG/50 wt.% G did not exhibit a measurable heat development. Particular attention was paid to effect separation between thermal conductivity and residue formation. Good thermal conductivity properties are proven to be particularly effective in test scenarios where the heat impact is comparatively low and the testing environment provides good heat dissipation and convective cooling possibilities. For candle-like ignition scenarios (e.g., LOI), filling levels of >50 wt.% (G or EG/G) are shown to be sufficient to suppress ignition exclusively by thermal conductivity. V0 classifications in UL-94 vertical burning tests were achieved for PA6 formulations containing ≥70 wt.% G, ≥25 wt.% EG and ≥20 wt.% EG/25 wt.% G.

Enhanced in-plane thermal conductivity of PP composites with high orientation and rational layered distribution of BNNS

Thermally conductive polymeric materials have attracted great interest from academia and industry for several decades. Herein, we report a facile method to fabricate BNNS/PP composites with excellent properties, especially the in-plane thermal conductivity. SEM and XRD results show the orderly dispersion and high orientation of BNNS along the in-plane direction. Attractively, the in-plane thermal conductivity of BNNS/PP composites after 20 times of folding and hot pressing is dramatically improved to 4.08 W/mk at a BNNS content of only 19.1 vol%, which is 20 times higher than that of pure PP and 480% higher than that of single hot pressing composite at the same filler content. In addition, The Hashin-Shtrikman (HS) model and finite element simulations are introduced to interpret the improvement of in-plane thermal conductivity of BNNS/PP composites after repeated hot pressing. Meanwhile, the influence of parallel orientation and layered distribution of BNNS on the mechanical and dielectric properties of BNNS/PP composites has been investigated. This facile method presents a novel approach to design and fabricate polymer composites with excellent in-plane thermal conductivity.

Electropolymerized 1,10-phenanthroline as the electrode material for aqueous supercapacitors

Research on novel conducting polymer material is essential in designing high-performance electrodes for the electrochemical energy storage systems. 1,10-phenanthroline is, for the first time, electropolymerized in aqueous solutions on carbon paper, and the resulting electrodes (PPhen/CP) are utilized to store energy electrochemically. The influence of the electropolymerization time and intercalated anions to the morphology and charge storage performance is investigated, and the results show that PPhen/CP with 20 min electropolymerization time and intercalated sulfate ions (PPhen/CP-20) exhibits the best performance, with the specific capacities estimated by galvanostatic charge–discharge of 111.5 mAh g−1 at 1 A g−1 in 1 M H2SO4, and of 97.1 mAh g−1 at 1 A g−1 in 1 M KOH. The solid-state supercapacitor assembled using two PPhen/CP-20 and the H2SO4/PVA gel electrolyte can deliver the energy density of 19.44 Wh kg−1 at the power density of 899.5 W kg−1, and can retain 80.76% of the initial capacity after cycling at 5 A g−1 for 4000 cycles. The charge storage mechanism involves dihydroxyl/diketone groups redox process and double layer charging, and the charge storage performance is affected by the electrochemically active surface area and diffusion processes which are related to the morphology of the electropolymerized film. This study shows that the electropolymerized 1,10-phenanthroline film is a promising candidate as the electrode material for aqueous supercapacitors.

Study on Fault Optimization of Intermediate Joint of Power Cable

Abstract Cable joints are often prone to failure due to loose contact, small contact area and increased contact resistance, resulting in obvious heating. In the existing cable emergency repair work, the cable joints of the original section of the cable and the access end are made on site. Due to the long production time, the emergency repair speed is reduced. Therefore, this paper studies the connection mode of the new cable joint to make the contact between conductors more sufficient and the contact resistance smaller, and designs a scheme of three-phase cable plug-in intermediate joint with high safety and simple installation; at the position of cable joint, three kinds of flexible conductive polymer materials suitable for joint connection are proposed to be used at the contact gap between conductor and conductor, conductor and conductor sleeve, so as to make close contact, reduce contact resistance and further reduce the incidence of cable joint failure.

Well-controlled Core-shell structures based on Fe3O4 nanospheres coated by polyaniline for highly efficient microwave absorption

In this paper, Fe3O4@polyaniline (Fe3O4@PANI) core–shell nanospheres have been successfully synthesized via a facile single mode microwave-assisted hydrothermal method following an in-situ free radical chemical oxidative polymerization, which are used as microwave absorption materials. Conductive polymer material PANI is uniformly coated on the surface of Fe3O4 nanospheres of 100 nm to form a core–shell structure. Microwave absorption ability of Fe3O4 nanospheres coated by the conductive PANI is significantly enhanced. The strongest reflection loss of Fe3O4@PANI core–shell nanospheres can reach −55.5 dB at the microwave frequency of 17.3 GHz under a low thickness of 1.6 mm. Moreover, the effective absorption bandwidth is up to 6.6 GHz under thickness of 1.5–2.0 mm. Fe3O4@PANI core–shell nanospheres with excellent microwave absorption properties are potential candidates at broad application of the high-frequency electromagnetic waves range.

Research and Application Analysis of Thermal Conductive Polymer Materials

Research and Application Analysis of Thermal Conductive Polymer Materials

Cross-linked composite proton conductive membranes

Using UV-curing technique the proton conductive polymer materials based on acrylic monomers: 2-acrylamido-2-methylpropane sulfonic acid (AMPS), acrylic acid (AA) and acrylonitrile (AN), cross-linked by varying amounts of N,N'-methylene(bis)acrylamide (MBA), and the hybrid polymer/inorganic membrane of the same content with addition of sol-gel system (SGS) based on 3-methacryloxypropyl trimethoxysilane (MAPTMS) and tetraethoxysilane (TEOS) were synthesized. The obtained materials were characterized by analysis of thermal, mechanical and morphological properties. Proton conductivity and water uptake were found to depend on the level of cross-linking of the materials. The value of proton conductivity of the hybrid membrane was sufficiently high reaching 3.46 × 10-2 S cm-1.

Recent Progress in Flexible Graphene-Based Composite Fiber Electrodes for Supercapacitors

Graphene has shown the world its fascinating properties, including high specific surface area, high conductivity, and extraordinary mechanical properties, which enable graphene to be a competent candidate for electrode materials. However, some challenges remain in the real applications of graphene-based electrodes, such as continuous preparation of graphene fibers with highly ordered graphene sheets as well as strong interlayer interactions. The combination of graphene with other materials or functional guests hence appears as a more promising pathway via post-treatment and in situ hybridism to produce composite fibers. This article firstly provides a full account of the classification of graphene-based composite fiber electrodes, including carbon allotropy, conductive polymer, metal oxide and other two-dimensional (2D) materials. The preparation methods of graphene-based composite fibers are then discussed in detail. The context further demonstrates the performance optimization of graphene-based composite fiber electrodes, involving microstructure design and surface modification, followed by the elaboration of the application of graphene-based composite fiber electrodes in supercapacitors. Finally, we present the remaining challenges that exist to date in order to provide meaningful guidelines in the development process and prospects of graphene-based composite fiber electrodes.

The Study of The Electrical Conductivity and Activation Energy on Conductive Polymer Materials

Conductive Polymers are one of the interesting topics to be developed in recent years. Conductive polymers can combine the properties of polymers and the electrical properties of metals. Research related to the electrical properties of conductive polymers, including electrical conductivity measurements and determination of activation energy has been carried out. This study aims to determine the effect of addition mass fraction of activated carbon into the nylon polymer on the conductive polymer material based on the electrical conductivity and activation energy. The variations of activated carbon used are 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% (wt/V). The conductive polymer from nylon polymer and activated carbon is made by casting solution method. The electrical conductivity measurement of the conductive polymer and the activation energy was carried out using the parallel plate method. The value of electrical conductivity increased from 5.62×10-9 ± 1.89×10-10 S/cm for the pure nylon to 2.51×10-8 ± 2.87×10-10 S/cm for the addition of mass fraction of activated carbon 8% wt/V. Meanwhile, there was a decrease in the addition of 9% wt/V and 10% wt/V of mass fraction of activated carbon, which were 2.36×10-8 ± 3.47×10-10 S/cm and 2.28×10-8 ± 4.01×10-10 S/cm. The activation energy of conductive polymer obtained decreased with increasing in the mass fraction of the activated carbon into the nylon polymer. The activation energy for the pure nylon was 0.0189 eV and 0.0127 eV for the addition of 8% wt/V mass fraction of activated carbon. Meanwhile, there was an increase in the addition of 9% wt/V and 10% wt/V mass fractions of activated carbon of 0.0145 eV and 0.0150 eV, respectively.

Au-assisted polymerization of conductive poly(N-phenylglycine) as high-performance positive electrodes for asymmetric supercapacitors

Herein, a novel conductive poly(N-phenylglycine) (PNPG) polymer was successfully prepared, by in situ electrochemical polymerization method (+0.75 V versus Ag/AgCl) for 10 min, on flexible stainless-steel plate coated with a thin Au film (Au/SS) to serve as a binder-free pseudocapacitive PNPG/Au/SS electrode for energy storage devices. Compared to the electrode without Au coating, PNPG/Au/SS electrode exhibited better electrochemical performance with larger specific capacitance (495 F g−1 at a current density of 2 A g−1), higher rate performance and lower resistance, which are good indications to act as a positive electrode for asymmetric supercapacitor devices. Combined with activated carbon as a negative electrode, an asymmetric supercapacitor device was constructed. It displayed a specific capacitance of 38 F g−1 at a current density of 0.5 A g−1 and an energy density of 5.3 Wh kg−1 at a power density of 250 W kg−1. Experimentally, two asymmetric supercapacitor devices were connected in series to power a home-made windmill continuously for 8 s, revealing the high potential of this novel conductive polymer material for energy storage application.

Comparison of gold and PEDOT:PSS contacts for high-resolution gastric electrical mapping using flexible printed circuit arrays.

Motility of the stomach is governed by an electrophysiological event termed gastric slow waves. High-resolution (HR) bioelectrical mapping involves placing array of electrodes over the surface of the stomach to record gastric slow waves. Conductive polymer materials have recently been applied to great effect in cardiology and neurophysiology due to its compliant and biocompatible properties. The aim of this study was to quantify the performance of poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) deposited on a flexible print circuit electrode array for gastric slow wave HR mapping. The Au electrodes were coated with PEDOT:PSS at 1 V and different levels of charges (0.3-1.2 mC). HR mapping alongside standard Au electrodes was performed in three anesthetized pigs. Overall, the PEDOT:PSS electrodes detected both antegrade and retrograde slow wave propagations, with comparable frequency, velocity and signal-to-noise ratio to the Au electrodes. Differences between the two electrodes were noted in terms of amplitude and downstroke gradient. The findings of this study will inform designs of future stretchable and implantable HR mapping electrode arrays for gastrointestinal recording and stimulation therapies.