Conducting Polymer Blends Research Articles

Conductive polymer blends with low carbon black loading: High impact polystyrene/thermoplastic elastomer (styrene‐isoprene‐styrene)

AbstractElectrical resistivity and morphology of high impact polystyrene (HIPS)/styrene‐isoprene‐styrene copolymer (SIS)/carbon black (CB) blends were studied. Conductive CB particles locale preferentially within the HIPS phase of the HIPS/SIS blends. The blends studied remain conductive as long as HIPS maintains a continuous phase and the effective CB concentration within HIPS surmounts its percolation threshold. Thus, blends containing 2 phr CB depict significant changes in resistivity with the HIPS/SIS composition, transforming from insulative to conductive. SIS/CB mixtures exhibit an unusual behavior, explained by a physical model suggested in this paper and extended to the HIPS/SIS/CB systems.

Conductive polymer blends prepared by in situ polymerization of pyrrole: A review

AbstractElectrically conductive polymer blends can be prepared by in situ polymerization of pyrrole within another polymer matrix. This may be accomplished using either electrochemical or chemical oxidative polymerization. This paper reviews the literature on this subject.

Charge transport and magnetic properties in polyaniline doped with methane sulphonic acidand polyaniline-polyurethane blend

Charge transport in polyaniline protonated fully with methane sulphonic acid (MSA) and polyaniline (MSA)-polyurethane [PANI(MSA)-PU] blend has been investigated through measurements of temperature (T) and electric field (E) dependence of conductivity (\ensuremath{\sigma}), temperature dependence of thermoelectric power and magnetic susceptibility and electron spin resonance at room temperature. PANI(MSA) exhibits a three-dimensional variable-range hopping (VRH) type of conduction, which is not the case with HCl-doped PANI and the electric field dependence of its conductivity is also consistent with VRH behavior. The thermopower in PANI(MSA) shows metallic behavior. The blend follows a one-dimensional VRH type of conduction and the electric field dependence of its conductivity exhibits the Poole-Frenkel effect. The temperature-dependent magnetic susceptibility measurements indicate the presence of Pauli and Curie spins in both the samples. From electron spin resonance measurements the percentage of Lorentzian and Gaussian spins have been estimated. In PANI-MSA a larger number of spins are found to be delocalized. The conduction mechanism in PANI-PU blend is discussed in comparison to other commercial conducting polymer blends.

Bipolar Conducting Polymers: Blends of p-Type Polypyrrole and an n-Type Ladder Polymer

Bipolar conducting polymers, in which both hole transport and electron transport contribute to electronic conductivity, have been explored by chemical template synthesis of p-type polypyrrole (PPy) in the matrix of an n-type conjugated ladder polymer, poly(benzimidazole−benzophenanthroline) (BBL). Transmission electron microscopy images of the conducting polymer blends show that 5−20 nm diameter × 100−180 nm long rodlike PPy particles are randomly and homogeneously distributed in the BBL matrix, with connectivity of the PPy phase occurring at a volume fraction of about 0.17. The volume fraction dependence of conductivity of the BBL/PPy blends did not exhibit a percolation threshold at volume fractions as low as 0.007 nor can it be described by percolation-type effective medium theory. Room temperature conductivities as high as 60−70 S/cm were observed in the blends compared to 2 S/cm in pure PPy. The enhanced conductivity and the nonpercolation nature of these blends originate from bipolar charge transport involving both conjugated polymer components of the blends. Existence of the oxidized (p-type) polypyrrole and reduced (n-type) BBL that facilitate bipolar charge transport in these blends was established by cyclic voltammetry.

Enhanced conductivity in conducting polymer blends induced by aluminum borate whiskers

The influence of a filler on melt-mixed conducting polymer blends of poly(3-octylthiophene) (POT) has been examined with respect to their morphology, rheology, conductivity and acid-base properties. The matrix polymers used were low density polyethylene (LDPE), poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) and the filler was non-conducting aluminum borate whiskers. These blends show two-phase behavior when examined by scanning electron microscopy. It was found that the adhesion at the polymer-filler interface in combination with the viscosity ratios between the polymers exerts a considerable influence on the morphology and hence on the conductivity. For the PE/POT blends, addition of whiskers changed the morphology and increased the conductivity by several orders of magnitude. The conductivity of blends with PVC was almost unchanged while the conductivity of PMMA blends slightly decreased upon addition of whiskers. The interactions between whiskers and the polymers used decreased in the order: PMMA > POT > PVC > PE. This is in accordance with the Lewis acid-base properties determined by inverse gas chromatography.

Structures and properties of the water-soluble self-acid-doped conducting polymer blends: sulfonic acid ring-substituted polyaniline/poly(vinyl alcohol) and poly(aniline- co- N-propanesulfonic acid aniline)/poly(vinyl alcohol)

Blends of the water-soluble self-acid-doped conducting polyanilines, sulfonic acid ring-substituted polyaniline (SPAN) and poly(aniline- co- N-propanesulfonic acid aniline) (PAPSAH), each with poly(vinyl alcohol) (PVA) were prepared and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, electronic spectroscopy, infra-red spectroscopy, thermogravimentric analysis, conductivity measurements, atomic force microscopy, and scanning tunnelling microscopy. It was found that the incorporation of PVA has no effect on the doping levels of SPAN and PAPSAH in the blends. This is due to the higher basicity of the N than OH, causing a more favourable interaction of the SO 3H group with N. The strong interaction of these polyanilines with PVA through hydrogen bonding between hydroxyl groups (of PVA) and amine and positively charged amine and imine sites (of SPAN and PAPSAH) leads to a decrease in hydrogen bonding among PVA subchains and to a partial miscibility. As the PVA content is higher than 70%, interconnected regions of PVA-rich phase and of SPAN-rich phase are formed such that the dilution effect of PVA on the conductivity is not large. Although SPAN has a much higher thermal undoping temperature (190°C) than PAPSAH (110°C), it reduces to 110°C in the blends due to the occurence of dehydration at this temperature, while for the blend of PAPSAH with PVA, its thermal undoping temperature remains unchanged.

Ac conduction properties of conducting polymer blends based on polyaniline

The composition and temperature dependence of the ac-conductivity of films of conducting polymer blends has been studied in the frequency range : 10 Hz – 18 GHz. The frequency dependence of the complex permittivity dramatically changes from a dielectric to a conducting behavior for a weight fraction of conducting polymer corresponding to the percolation threshold p c determined by dc-conductivity measurements. The high frequency dispersion of the ac-conductivity, characteristic of disordered conductors is recovered. In addition, a “relaxation” process is observed at intermediate frequencies, which can be of rather high amplitude for weight fractions slightly above p c . The “fractal” nature of the conducting polymer net seems to be responsible for this behavior.

Highly conducting polymer blend films of polyaniline and nylon 6 by cosolvation in an organic acid

Polymer blend films of polyaniline and nylon 6 were prepared from homogeneous solutions in formic acid at various weight ratios of polyaniline and nylon 6. Free standing, lustrous and flexible films were obtained by casting. The maximum conductivity of the film was about 0.2 S cm −1, corresponding to a weight ratio of 0.5 wt/wt polyaniline (PAni) and nylon 6. The film exhibits semiconducting behaviour in the range of temperatures between 300 K and 10 K and the data fits in with the VRH model for transport in the range of 150 K to 50 K. Optical absorption spectra reveal absorption bands typical of polyaniline salt. I.r. spectra show a characteristic band at 1145 cm −1 which is associated with electrical conductivity in polyaniline. A simultaneous t.g.a.-d.t.a. scan reveals that the melting temperature of PAni/nylon 6 is slightly reduced. The X-ray diffraction pattern indicates that the crystal structure of nylon 6 in the blend film is retained on modification. The films also exhibit good environmental stability and mechanical strength.

X-ray photoelectron spectroscopic investigation of conducting polymer blends.

Electrochemically prepared films of conducting polymers of polypyrrole and polythiophene and their blends with polyamide have been investigated by X-ray photoelectron spectroscopy. In the N1s region of the spectra of films containing polypyrrole the peak corresponding to N(+) at 402.0 eV is separated from that of neutral N. The intensity of the N(+) peak can be correlated with the electrical conductivity of the films and the spectroscopically derived ratio of F/N(+) is close to 4 indicating that one BF(-)(4) dopant ion is incorporated for every oxidized nitrogen center. In the spectra of films of polythiophene and its blends peaks corresponding to S and S(+) can not be resolved but again the F/C ratio correlates with the electrical conductivity.

Conductive polymer blends with low carbon black loading: Polypropylene/polyamide

AbstractThe electrical resistivity and morphology of polypropylene/nylon (PP/Ny) immiscible blends incorporated with carbon black (CB) were studied. CB was found to be preferentially located in the Ny phase or upon the Ny/PP interface. Blends with a co‐continuous phase morphology depicted especially low resistivity values, due to a “double percolation” effect. The blend preparation sequence tends to affect the phase morphology, thus influencing the system's resistivity. Polymer polarity and crystallinity are important factors determining the blend's morphology, which relates directly to the electrical resistivity obtained.

Thermal stability of polyaniline networks in conducting polymer blends

The thermal stability of polyaniline-camphor sulfonic acid (PANI-CSA) networks in blends with poly (methyl methacrylate) (PMMA) and a low molecular weight polyester (PES ) has been studied by transmission electron microscopy (TEM) supplemented with measurements of the optical and electrical properties. The tenuous interpenetrating fibrillar network of PANI-CSA is robust and remains intact at temperatures above the glass transition temperature ( T g) and the melting point ( T m) of the host polymers ( T g~90 °C for PMMA; T m~60 °C for PES), indicating that the phase-separated network morphology is a thermodynamically stable phase. Although deprotonation of the PANI gradually starts around 100 °C, the network morphology persists (with crystallites of CSA, released by the deprotonation, distributed within the network). After exposure to increasingly higher temperatures, especially above 200 °C, the fibrils of the network coarsen, and the structure becomes more open. Complete deprotonation and degradation of the PANI are observed at temperatures above 200 °C. The conclusions from the TEM micrographs are consistent with thermal gravimetric analysis, spectroscopic data and electrical conductivity measurements.

Morphology and Macroscopic Properties of Conducting Polymer Blends

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTMorphology and Macroscopic Properties of Conducting Polymer BlendsMark A. Knackstedt and A. P. RobertsView Author Information Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, AustraliaCite this: Macromolecules 1996, 29, 4, 1369–1371Publication Date (Web):February 12, 1996Publication History Received31 August 1995Revised6 December 1995Published online12 February 1996Published inissue 1 January 1996https://doi.org/10.1021/ma951295hCopyright © 1996 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views452Altmetric-Citations45LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (2 MB) Get e-AlertsSUBJECTS:Electrical conductivity,Interfaces,Morphology,Polymer morphology,Polymers Get e-Alerts

Preparation and Properties of Conducting Polymer Blends of Polyaniline in Poly(vinyl formal) or Poly(methacrylic acid)

Preparation and Properties of Conducting Polymer Blends of Polyaniline in Poly(vinyl formal) or Poly(methacrylic acid)

Self‐assembled networks of conducting polyaniline in bulk polymers: A new class of conducting polymer blends

AbstractThis review of the current status of conducting polymers will focus on recent progress which demonstrates that the initial promise of the late 1970's has become reality. Conducting polymers are now available as materials with truly unique properties: They combine the important electronic and optical properties of semiconductors and metals with the attractive mechanical properties and processing advantages of polymers. Conducting polymer blends based upon polyaniline (PANI) are a new class of materials in which the threshold for the onset of electrical conductivity (σ) can be reduced to volume fractions below 1%, well below that required for classical percolation (16% by volume for globular conducting objects dispersed in an insulating matrix in three dimensions). The origin of this remarkably low threshold for the onset of electrical conductivity is the self‐assembled network morphology of the PANI polyblends which forms during the course of liquid‐liquid separation. Since the average density of the conducting network near threshold is small, the conductivity increases smoothly and continuously over many orders of magnitude as the concentration of conducting polymer increases above threshold. The low percolation threshold and the continuous increase of σ(f) above threshold are particularly important; as a result of this combination, conducting polyblends can be reproducibly fabricated with controlled levels of electrical conductivity while retaining the desired mechanical properties of the matrix polymer.1‐3)

Phase behaviors and interactions of N‐alkylated polyanilines and ethylene‐co‐vinyl acetate blends

AbstractConjugated polyanilines bearing long alkyl side chains (dodecyl PANi‐12 and octadecyl PANi‐18) were prepared for the purpose of obtaining well‐mixed conducting polymer blends with insulating flexible polymers. The miscibility of the polyanilines and ethylene‐co‐vinyl acetate copolymers (EV A20 with 20 wt % of vinyl acetate and EV A70 with 70 wt %) was significantly improved by long alkyl chains of the same hydrocarbon moieties as the ethylene segments in the matrix EV A, as demonstrated by microscopic observation. PANi‐18/EV A20 blends exhibit a lower critical phase separation temperature (LCST). In addition, the EV A crystallinity and the side‐chain crystallinity in the miscible blends were depressed, as shown by thermal analysis and x‐ray scattering. The comparison of three designed blend systems indicates that the miscibility of the polymers is determined by the hydrophobic interaction between the hydrocarbon units in the both components and by the hydrogen bonding. The solvatochromic phenomena for the blends at low miscible PANi compositions was detected by UV‐visible spectroscopy. The threshold conductivities exhibit sensitivity to the morphological structure of the polymeric blends, and was lowered by improved homogenous dispersion of the conducting phase. © 1995 John Wiley & Sons, Inc.

Conducting polymer blends of poly(3-octylthiophene) and poly(vinyl chloride) and the influence of a plasticizer on the compatibility

Meltmixed conducting polymer blends of poly(3-octylthiophene), POT, and poly(vinyl chloride), PVC, have been examined according to their conductivity, miscibility behaviour and their morphology. After doping with FeCl 3, these blends show a relatively high conductivity (∼3 S/cm for 23% POT). Phase structure and miscibility have been studied with electron microscopy and dynamic mechanical measurements, respectively. These studies reveal that POT and PVC form an immiscible blend which can be co-continuous even with a relatively low content of POT. By adding the plasticizer di-iso-octyl phthalate, DOP, the conductivity can be increased even if the content of POT is decreased.

Conductive composites based on PVDF-C 2F 3H and subtituted or pure poly(pyrroles)

Conducting polymer blend (alloy) films of poly(pyrrole) or derivatives with the insulating matrix PVDF-C 2F 3H, were synthesized (produced) by electrochemical polymerization of pyrrole or derivates on an electrode covered with the insulating film. The optimizations of the electrochemical polymerization and of the conductivities of the materials were studied. There electrical behaviors were observed at low temperature. The thermal stability of polypyrrole is improved in the high temperature region when it is incorporated in the fluorinated copolymer.

Transports in blends of conducting polymers

We investigated the transport properties of solution-processed conductive polymer blends of polyaniline-(camhpor sulfonic acid), PANI-CSA, with insulating polymethylmethacrylate (PMMA), as a function of various volume fraction (ƒ) of PANI-CSA. Due to the phase separated morphology and the fibrillar geometry of percolating objects, a self-assembled PANI-CSA network in insulating matrix shows extremely low percolation threshold (ƒ c ≈ 0.003). The characteristic metallic properties of pure PANI-CSA, such as positive temperature coefficient of resistivity at high temperature, linear temperature dependence of thermoelectric power, and frequency independent ac conductivity, are retained in PANI-CSA/PMMA blends down to ƒ c. At low temperature, the hopping transports through the conducting polymer network depends on the volume fraction of PANI-CSA in blends and its network structure.

Electrically Conducting Polymer Blends Based On Polyaniline

ABSTRACTPolyaniline offers a promissing possibility to make electrically conducting polymer blends with tailorable surface and bulk conductivities. The matrix polymer can be a thermoplast or a thermo- set. Different commonly used polymer processing methods are applicable to the blends; e.g. injection moulding, film blowing, compression moulding and fiber spinning. Also commonly used thermoset resins processings are possible. The key feature in making all this feasible is the co- solvent/plasticizer technology developed recently in the industry. Typically, the antistatic conduc- tivity level is reached in melt-processing with a polyaniline complex amount of 5 to 10 wt-% and in solution processing with 0.5 to 5 wt-% complex amounts. The maximum conductivity is in the range of 10 to 100 mS/cm for blends.

Superlocalization of the electronic wave functions in conductive polymer blends at concentrations near the percolation threshold

The ability to solution-process polyaniline (PANI) in the protonated conducting form through the use of surfactant counterions has enabled the fabrication of conductive polymer blends with a percolation threshold at a volume fraction near 1%. Electron micrographs of blends of PANI complexed with camphorsulfonic acid (CSA) in poly(methyl methacrylate) show a tenuous interconnected network; for concentration of PANI-CSA near the percolation threshold, the network is self-similar. Digital analysis of the micrographs shows that in thin two-dimensional ``slices`` the PANI-CSA networks are fractal, with the area (S) of the conducting network varying as S {alpha} r{sup D}, where D < 2 for concentrations below 4%. Near the threshold, they find D {approximately} 1.5, implying a fractal dimensionality in three dimensions of ca. 2.5. The electrical conductivity of these blends follows the Mott-Deutscher model for variable-range hopping on a fractal network, {sigma}(T) {approximately} exp[{minus}(T{sub 0}/T){sup {gamma}}]. They find that {gamma} increases from {gamma} = 1/4 in pure PANI-CSA (indicting variable-range hopping among exponentially localized states) to {gamma} {approximately} 2/3 as the PANI-CSA concentration is reduced to the percolation threshold, indicating variable-range hopping among superlocalized states on the fractal structure in the limit where the Coulomb interaction between the electron and the holemore » dominates the intersite hopping.« less