Conducting Polymer Composite Films Research Articles

Impedanciometric Study of Conducting Polymer Composite Films from Cassava Starch/ Poly (3,4-Ethylenedioxythiophene)

Impedanciometric Study of Conducting Polymer Composite Films from Cassava Starch/ Poly (3,4-Ethylenedioxythiophene)

Electrically Conductive Graphene-Based Biodegradable Polymer Composite Films with High Thermal Stability and Flexibility

Cellulose nanofibril (CNF) and graphene (GR) powder were added into polylactic acid (PLA)/polypyrrole (PPy) composite films via a low-cost, eco-friendly, low-temperature, and in-situ polymerization synthesis, which obtain novel flexible and conductive polylacticacid-cellulose nanofibril-graphene/polypyrrole (PLA–CNF–GR/PPy) composite films. The CNF was embedded in the PLA matrix to enhance the mechanical properties. Remarkably, when a few GR (1%) powder was added, the tensile strength of composite films increased by 5.6%, respectively, compared with pure PLA–CNF, and increased by 17.6% compared with the PLA. The GR and CNF had a positive influence on mechanical properties of composite films. In addition, the PLA–CNF–GR/PPy composite films exhibited many unique properties when GR powder was introduced, including high thermal stability, and especially electrical conductivity. The electrical conductivity of the PLA–CNF–GR/PPy composite films increased from 0.12 to 1.06[Formula: see text]S/cm as the content of GR powder increased from 0 to 10%. The PLA–CNF–GR-10/PPy also demonstrated excellent flexible stability, only 7.5% deviation after over 100 bending cycles. Furthermore, we designed and found that the exploration of a flexible solid-state supercapacitor assembled with PLA–CNF–GR-10/PPy composite electrodes had a capacitance of 30[Formula: see text]F/g at a current density of 0.5[Formula: see text]A/g. Although it was not quite as prominent as the capacitance, it provided an innovative means for preparing the conductive composite films. Based on these advantages the PLA–CNF–GR/PPy could be considered as sensors, flexible electrodes, and flexible displays. It also opens a new field of potential applications of biodegradable materials.

Electrospinning and solid state polymerization: A simple and versatile route to conducting PEDOT composite films

Conducting polymer composite films containing poly(3,4-ethylenedioxythiophene) (PEDOT) was prepared by solid state polymerization (SSP) of 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) in the matrices of polystyrene (PS), sulfonated polystyrene (SPS), or poly(methyl methacrylate) (PMMA). A thin fiber mat was first fabricated by electrospinning a mixed solution of the polymer matrix and DBEDOT on glass slides. The SSP of the DBEDOT embedded in the polymer matrix was then induced by heating at 60–80°C, which resulted in a dark blue PEDOT composite film, structurally confirmed by Raman spectroscopy and X-ray diffraction spectroscopy. It was found that compression during heating produced better dispersed PEDOT particles in the polymer matrix. The conductivity of the composite fiber was found to reach as high as approximately 13, 14 and 32S/cm for the PEDOT/PS, PEDOT/SPS and PEDOT/PMMA composite films, respectively. These conductivity values are comparable to that of the pure PEDOT generated directly by SSP in the absence of a polymer matrix.

Electrochemical synthesis of Sm2O3 nanoparticles: Application in conductive polymer composite films for supercapacitors

A novel electrosynthetic method was introduced to synthesize of Sm2O3 nanoparticles and furthermore, for improving the electrochemical performance of conductive polymer, hybrid POAP/Sm2O3 films have then been fabricated by POAP electropolymerization in the presence of Sm2O3 nanoparticles as active electrodes for electrochemical supercapacitors. The structure, morphology, chemical composition of Sm2O3 nanoparticles was examined. Surface and electrochemical analyses have been used for characterization of Sm2O3 and POAP/Sm2O3 composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. The supercapacity behavior of the composite film was attributed to the (i) high active surface area of the composite, (ii) charge transfer along the polymer chain due to the conjugation form of the polymer and finally (iii) synergism effect between conductive polymer and Sm2O3 nanoparticles.

Flexible, Ultrathin, and High-Efficiency Electromagnetic Shielding Properties of Poly(Vinylidene Fluoride)/Carbon Composite Films.

In this study, we fabricated conductive poly(vinylidene fluoride) (PVDF)/carbon composites simply by dispersing multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets into a PVDF solution. The electrical conductivity and the electromagnetic interference (EMI) shielding of the PVDF/carbon composites were increased by increasing the conductive carbon filler amounts. Moreover, we also found that the EMI shielding properties of the PVDF/CNT/graphene composites were higher than those of PVDF/CNT and PVDF/graphene composites. The mean EMI shielding values of PVDF/5 wt %-CNT, PVDF/10 wt %-graphene, and PVDF/CNT/graphene composite films with a thickness of 0.1 mm were 22.41, 18.70, and 27.58 dB, respectively. An analysis of the shielding mechanism showed that the main contribution to the EMI shielding came from the absorption mechanism, and that the EMI shielding could be tuned by controlling the films' thickness. The total shielding of the PVDF/CNT/graphene films increased from 21.90 to 36.46 dB as the thickness was increased from 0.06 mm to 0.25 mm. In particular, the PVDF/carbon composite films, with a thickness of 0.1 mm, achieved the highest specific shielding values of 1 310 dB cm2/g for the PVDF/5 wt %-CNT composite and 1 557 dB cm2/g for the PVDF/CNT/graphene composite, respectively. This was due to the ultrathin thickness. Our study provides the groundwork for an effective way to design flexible, ultrathin conductive polymer composite film for application in miniaturized electronic devices.

Multi-material micro-electromechanical fibers with bendable functional domains**This article belongs to the Special Issue: Emerging Leaders, which features invited work from the best early-career researchers working within the scope of J. Phys. D. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Fabien Sorin was selected by the Editorial Board of J. Phys. D as

The integration of increasingly complex functionalities within thermally drawn multi-material fibers is heralding a novel path towards advanced soft electronics and smart fabrics. Fibers capable of electronic, optoelectronic, piezoelectric or energy harvesting functions are created by assembling new materials in intimate contact within increasingly complex architectures. Thus far, however, the opportunities associated with the integration of cantilever-like structures with freely moving functional domains within multi-material fibers have not been explored. Used extensively in the micro-electromechanical system (MEMS) technology, electro-mechanical transductance from moving and bendable domains is used in a myriad of applications. In this article we demonstrate the thermal drawing of micro-electromechanical fibers (MEMF) that can detect and localize pressure with high accuracy along their entire length. This ability results from an original cantilever-like design where a freestanding electrically conductive polymer composite film bends under an applied pressure. As it comes into contact with another conducting domain, placed at a prescribed position in the fiber cross-section, an electrical signal is generated. We show that by a judicious choice of materials and electrical connectivity, this signal can be uniquely related to a position along the fiber axis. We establish a model that predicts the position of a local touch from the measurement of currents generated in the 1D MEMF device, and demonstrate an excellent agreement with the experimental data. This ability to detect and localize touch over large areas, curved surfaces and textiles holds significant opportunities in robotics and prosthetics, flexible electronic interfaces, and medical textiles.

Enhanced Electromagnetic Interference Shielding in a Au–MWCNT Composite Nanostructure Dispersed PVDF Thin Films

Electromagnetic interference (EMI) shielding effectiveness and conductivities in a flexible conducting polymer composite film, prepared via a simple solvent cast method, of PVDF incorporated with Au–MWCNT are studied. The scanning electron microscopic analysis showed that the Au-loaded MWCNT uniformly dispersed in PVDF. The HRTEM images show that Au nanoparticles having a particle size of 20–30 nm have been deposited on the nodes of the MWCNT. The values of dielectric constant were found to be 12.11 and 13.89 at 1 MHz upon the incorporation of 1 and 3 wt % MWCNT in PVDF. The impedance and electromagnetic interference shielding effectiveness studies reveal that the polymer nanocomposites possess enhanced conductivity of 1.12 × 10–4 S/cm at 1 MHz, minimum return loss of 4.4 dB, and effective electromagnetic shielding of 26.7 dB at 12 GHz for 3 wt % Au NPs in 3 wt % MWCNT/PVDF thin film.

Preparation and Properties of Graphene/Polyurethane Conductive Polymer Composite Films

In this study, graphene was prepared by Hummers method and modified by silane coupling agent to introduce vinyl group. Polyurethane copolymer was used as adhesive to crosslink graphene layers, and their composite was synthesized with isophorone diisocyanate, polyethylene glycol (PEG400) and 2-hydroxyethyl methacrylate. Composite films were cast on glass substrate and cured after UV irradiation, which demonstrated satisfactory conductivity, transparency and thermal resistance properties as functionalized graphene homogeneously dispersed in polymer matrix and a conductive path was successfully constructed.

Swift heavy ion induced modifications in metal conducting polymer composite films

Au–polyaniline (Au–PANI) thin films were prepared by an electrochemical process. Au–PANI films were irradiated with 100MeV O7+ and 120MeV Ni9+ ion beams with fluences varying from 3×1011ions/cm2 to 3×1012ions/cm2. The effects of heavy ions on the structural, chemical and morphological properties of the composite films were studied by using X-ray diffraction, Raman and scanning electron microscopy techniques. X-ray spectra showed the gradual decrease in the peak intensity after irradiation. The interchain distance, interplanar distance, micro strain, dislocation density and distortion parameters were calculated. The analysis revealed a noticeable changes in these parameters after irradiation for both cases. The results showed the formation of clusters with a porous structure after irradiation. The effect of irradiation was greater in case of 120MeV Ni9+ rather than 100MeV O7+ ions due to their high electronic energy loss in Au–PANI. I–V characteristic measurements were carried out as a function of ion fluence. The results are discussed on the basis of linear energy transfer (LET) of the irradiated ions.

Electrochemical synthesis of conducting natural rubber nanocomposite films

Homogeneous conducting polymer composite films with improved electrical properties are synthesised by electrochemical polymerisation of aniline on natural rubber. The electrochemical polymerisation is carried out by potentiostatic method using an aqueous solution of 0·1M aniline and 1M sulphuric acid as electrolyte in a single compartment electrochemical cell with steel electrode for collecting the polymer composite. The redox behaviour and stability of the film are studied by cyclic voltammetry. The morphological and spectroscopic analysis revealed an effective formation of the composite. The interfacial properties and ac conductivity of the deposited films are studied by impedance spectroscopy.

In situ fabrication of conducting polymer composite film as a chemical resistive CO2 gas sensor

In this study, an easy to fabricate and low-cost, resistive-type CO2 gas sensor made of poly(3,4-ethylenedioxythiophene) (PEDOT) and branched polyethylenimine (BPEI) layers was fabricated on an interdigitated electrode. The PEDOT film was made by in situ polymerization and the BPEI layer was subsequently drop-coated on top of the PEDOT film. Upon exposure to 1000ppm CO2 at 95% relatively humidity (RH) of the BPEI–PEDOT composite sensor, the synergistic effect of BPEI on CO2 sensing was subsequently investigated. The sensors showed no response (i.e. % of conductivity increase) if the sensor film was only made of a PEDOT layer without any BPEI. However, the response increased significantly to a value of 3.25% upon the addition of a layer of BPEI. The sensors also showed no obvious decay in the sensing response during repeated usages, providing the reusability of the technique for CO2 detection. As for sensor’s selectivity, the sensors showed higher response for CO2 than for O2. Originally, the sensor showed a long recovery time of nearly 1h. However, the long recovery time can be significantly shortened to approximately 10min by heating the sensors at higher temperature for CO2 desorption. Thus, this easy and inexpensive fabrication process demonstrated that the sensor might have characteristics sufficient for real-world CO2 detection.

Conducting polymer composite film incorporated with aligned carbon nanotubes for transparent, flexible and efficient supercapacitor.

Polyaniline composite films incorporated with aligned multi-walled carbon nanotubes (MWCNTs) are synthesized through an easy electrodeposition process. These robust and electrically conductive films are found to function as effective electrodes to fabricate transparent and flexible supercapacitors with a maximum specific capacitance of 233 F/g at a current density of 1 A/g. It is 36 times of bare MWCNT sheet, 23 times of pure polyaniline and 3 times of randomly dispersed MWCNT/polyaniline film under the same conditions. The novel supercapacitors also show a high cyclic stability.

Building up Graphene‐Based Conductive Polymer Composite Thin Films Using Reduced Graphene Oxide Prepared by γ‐Ray Irradiation

In this paper, reduced graphene oxide (RGO) was prepared by means of γ-ray irradiation of graphene oxide (GO) in a water/ethanol mix solution, and we investigated the influence of reaction parameters, including ethanol concentration, absorbed dose, and dose rate during the irradiation. Due to the good dispersibility of the RGO in the mix solution, we built up flexible and conductive composite films based on the RGO and polymeric matrix through facile vacuum filtration and polymer coating. The electrical and optical properties of the obtained composite films were tested, showing good electrical conductivity with visible transmittance but strong ultraviolet absorbance.

Proton and Electron Conducting Polymer Composite Films Based on SBS Triblock Copolymer

AbstractSummary: Conducting polymer films were prepared by introducing ionic groups via chemical modification of one of the blocks of the polystyrene‐block‐polybutadiene‐block‐polystyrene (SBS) triblock copolymer and by adding different amount of metal salts into the modified block copolymer. The butadiene part of the copolymer was partially sulphonated to prepare the proton conducting film while the epoxidized form was used to fabricate electron conducting films with different inorganic salts. The products were characterized by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and potential as well as conductivity measurements.

Battery Characteristics of Nanocrystalline V2O5 and Conductive Polymer Composite Film Cathodes

Composite films of nanocrystalline V2O5 embedded in a conducting polymer, poly-3,4-ethylenedioxythiophene (PEDOT), were grown using an electrochemical polymerization method. The nanobeam-shaped V2O5 and PEDOT composite film cathodes have high capacities, excellent rate capabilities and cycling stabilities: the specific capacity was 269 mAhg-1 and the degradation rate was only 8% after 100 consecutive cycles at 1 C rate. The charge transfer resistances (Rct) for the nanobeam-V2O5/PEDOT composite film cathodes were smaller than that for the nanobeam-V2O5 powder cathode, in the electrochemical impedance measurements. The diffusion coefficient (DLi+) in the nanobeam-V2O5 crystallines was calculated to be approximately 4.6 x 10-8, and the values of DLi+ for each of α-, ε-, and δ-LixV2O5 crystalline phases, reversibly formed in the composite films during the discharging and charging processes, were able to be estimated in the range of (2.1~9.8) x 10-10.

Study on the preparation and multiproperties of the polypyrrole films doped with different ions

Conducting polypyrrole (PPy) films doped with p‐toluene solfonate (pTS−), perchlorate (ClO4−) and polyphosphate (PP−) were electrochemically synthesized on the stainless steel SS‐304 and the Indium Tin Oxide (ITO) glass substrates successfully. The conducting polymer composite films were studied by Fourier transform infrared spectra, integrated thermal analysis system and scanning electron microscopy, respectively. Four‐point probe measurements and in situ nanotribolab system equipped with a nanoscale electrical contact resistance package were employed to analyze their electrical and mechanical properties. Results indicate that the film doped with PP− ion showed the best thermal stability. For the ClO4− ion doped films, the glass transition occurred at 274.8 °C. The pTS− ion doped film on the SS‐304 steel had a good conductivity, and there was a voltage barrier that ranged from −1.25 to 1.9 V according to the current–voltage curves. Nanoindentation tests show that the mechanical properties of the PPy/pTS− film and the PPy/PP− film were better than that of PPy/ClO4− films. Copyright © 2012 John Wiley & Sons, Ltd.

Superoleophobic and conductive carbon nanofiber/fluoropolymer composite films

A solution-based, large-area coating procedure is developed to produce conductive polymer composite films consisting of hollow-core carbon nanofibers (CNFs) and a fluoroacrylic co-polymer available as a water-based dispersion. CNFs (100 nm dia., length ∼130 μm) were dispersed by sonication in a formic acid/acetone co-solvent system, which enabled colloidal stability and direct blending of the CNFs and aqueous fluoroacrylic dispersions in the absence of surfactants. The dispersions were sprayed on smooth and microtextured surfaces, thus forming conformal coatings after drying. Nanostructured composite films of different degrees of oil and water repellency were fabricated by varying the concentration of CNFs. The effect of substrate texture and CNF content on oil/water repellency was studied. Water and oil static contact angles (CAs) ranged from 98° to 164° and from 61° to 164°, respectively. Some coatings with the highest water/oil CAs displayed self-cleaning behavior (droplet roll-off angles <10°). Inherent conductivity of the composite films ranged from 63 to 940 S/m at CNF concentrations from 10 to 60 wt.%, respectively. Replacement of the long CNFs with shorter solid-core carbon nanowhiskers (150 nm dia., length 6–8 μm) produced stable fluoropolymer–nanowhisker dispersions, which were ink-jetted to generate hydrophobic, conductive, printed line patterns with a feature size ∼100 μm.

Structure–property relationship in aliphatic polyamide/polyaniline surface layered composites

Conducting polymer composite films based on different aliphatic polyamides (PA) (PA-6, PA-11 and PA-12) have been synthesized by in situ aniline polymerization inside a surface layer of the PA host matrix. Dielectric permittivity and dielectric loss of these films are explained in terms of the interfacial polarization. The real part of permittivity is found to be higher in the PA/polyaniline (PANI) composite films than in the virgin PA polymer matrix. Such behaviour is attributed to the interaction between PA and PANI molecular chains and to the conductivity increase after the aniline polymerization. The performed confocal Raman spectrometry and X-ray diffraction studies also confirmed the presence of interactions between PA and PANI molecular chains.

Fabrication and characterization of organic semiconductor for electromagnetic interference shielding material

Abstract Conducting polymer films produced by electropolymerization technique are highly conductive, simple, and suitable for use especially in electronic devices. An attempt has been made to produce polypyrrole-poly(vinyl alcohol) (PPy-PVA) conducting polymer composite films using 0.1 m p-toluene sulfonate dopant at a potential of 1.2 V (vs. standard calomel electrode) on indium tin oxide glass electrode. The potential application of the prepared PPy-PVA conducting polymer composite films as an electromagnetic interference (EMI) shielding material has been investigated in the present study. The EMI shielding effectiveness of PPy-PVA composite films prepared from different experimental conditions was analyzed in the microwave frequency range of 8–12 GHz. The shielding effectiveness of 45.67–35.7 dB has been demonstrated by PPy-PVA conducting polymer composite films, which appears to be very attractive in any EMI shielding applications where a minimum shielding effectiveness of 35 dB is required.

Battery Characteristics of Nanocrystalline V2O5 and Conductive Polymer Composite Film Cathodes

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