Conducting polymer embedded with nanoferrite and titanium dioxide nanoparticles for microwave absorption

The present paper deals with the synthesis of conducting ferrimagnetic polyaniline nanocomposite embedded with γ-Fe₂O₃ (9–12 nm) and titanium dioxide (70–90 nm) nanoparticles via a micro-emulsion polymerization. The microwave absorption properties of nanocomposite in 12.4–18 GHz (Ku-band) frequency range shows shielding effectiveness due to absorption (SE_A) value of ?45 dB, which is much higher than polyaniline composite with iron oxide and polyaniline–TiO₂ composites. The higher EMI shielding is mainly arising due to combined effect of γ-Fe₂O₃ and TiO₂ that leads to more dielectric and magnetic losses which consequently contributed to higher values of shielding effectiveness. XRD analysis of the nanocomposite reveals the incorporation of nanoparticles in the conducting polymer matrix while the thermal gravimetric analysis (TGA) demonstrates that the nanocomposite is stable up to 250 °C.     

Electrical conductivity and dielectric response of poly(vinylidene fluoride)–graphite nanoplatelet composites

Poly(vinylidene fluoride)/graphite nanoplatelets (PVDF/GNP) composites were fabricated using solution mixing followed by compression molding. The electric conducting and dielectric behavior of such nanocomposites were determined over a wide frequency range from 10² to 10⁷. The results showed that the electrical behavior of PVDF/GNP nanocomposites can be well described by the percolation theory. Both conductivity and dielectric constant were found to be greatly enhanced at the percolation threshold. A large dielectric constant of 173 and low loss tangent of 0.65 were observed in the PVDF/2.5 wt% GNP nanocomposite at 1 kHz. Moreover, dynamic mechanical analysis was also used to characterize the relaxations of polymers in PVDF/GNP nanocomposites. Dielectric and mechanical relaxations of PVDF/GNP nanocomposites showed strong dependence with frequency and temperature. The activation energy for glass transition determined from mechanical relaxation is considerably higher than that evaluated from the dielectric analysis. This resulted from different operating mechanisms for dielectric and mechanical relaxation processes.     

Synthesis of potential capacitive Poly 4, 4′-diaminodiphenyl sulphone–metal nanocomposites and their characterizations

4, 4′-Diaminodiphenyl sulphone was polymerized (with lithium/cobalt/lithium–cobalt salts) by chemical oxidation method using potassium perdisulphate. The solubility of the chemically prepared polymer–metal nanocomposite was ascertained and it showed good solubility in DMF, chloroform, trichloroethylene and DMSO. The PDDS–Li/Co/Li–Co nanocomposites were characterized by UV–vis and FTIR spectral studies. Amine and imine vibrations observed at 1593 and 1503 cm^?1 were shifted to lower wave numbers when the polymer–metal composites were formed. A single absorption peak due to the N–H stretching vibration of the imino groups of polymer–metal nanocomposite is observed around 3459 cm^?1 and it suggests the participation of NH group during polymerization. The X-ray diffraction studies revealed the formation of nano sized (82 nm) crystalline polymer. The conductivity of the PDDS–Li–Co nanocomposite was determined to be 6.26 × 10^?2 S cm^?1. SEM analysis showed mixed granular nature of the polymer–metal nanocomposite. The capacitance (159.04 μF) of chemically synthesized PDDS–Li–Co nanocomposite is suggested as a potential capacitive material.     

Conductive polymer-coated textiles: The role of fabric treatment by pyrrole-functionalized triethoxysilane

Polypropylene (PP) and viscose (VS) textiles were modified by the in situ synthesis of a conducting polypyrrole (PPy) overlayer. To improve adhesion of the conducting layer to the textile surface, a pyrrole-functionalized silane (SP) was synthesized and bonded onto the surface before polypyrrole formation. Moreover, to introduce hydroxyl groups into the surface, PP was pretreated by grafting vinyltrimethoxysilane by means of a radiofrequency plasma discharge. The study is focused on the influence of SP on the washing fastness of a PPy layer and, consequently, on the overall conductivity of the textiles after washing. In the case of viscose, PPy was found to penetrate the substrate. A compromise was found between the influence of SP and penetration phenomenon (best conductivity after washing: wVS–0.2SP/25Py = 3 × 10⁻⁵ S/square). In the case of polypropylene the effect of pretreatment with SP is much better than for viscose, and a higher concentration of SP leads to improved fastness of the conductive layer (wmPP–0.2SP/25Py = 3 × 10⁻⁵ S/square; wmPP–1SP/25Py = 8 × 10⁻⁵ S/square), which indicates that the coating promoted by means of SP is more favoured than for viscose.     

Conducting polymer functionalized multi-walled carbon nanotubes with noble metal nanoparticles: Synthesis,morphological characteristics and electrical properties

We report the synthesis of conducting polyaniline-functionalized multi-walled carbon nanotubes (MWCNTs-f-PANI) containing noble metal (Au and Ag) nanoparticles composites (MWCNTs-f-PANI-Au or Ag-NC). MWCNTs-f-PANI was initially synthesized by functionalizing acyl chloride terminated carbon nanotubes (MWCNTs-COCl) with 2,5-diaminobenzenesulphonic acid (DABSA) via amide bond formation, followed by surface initiated in situ chemical oxidative graft polymerization of aniline in the presence of the ammonium persulphate (APS) as an oxidizing agent. MWCNTs-f-PANI was then dispersed into an aqueous Au or Ag metal salt solution followed by the addition of sodium citrate, which acted as a reducing agent. The resulting composite contained a high level of well dispersed Au or Ag nanoparticles (MWCNTs-f-PANI/Au-NC or MWCNTs-f-PANI-Ag-NC). Morphological and structural characteristics, as well as electrical conducting properties of the hybrid nanocomposites were characterized using various techniques including high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–visible spectroscopy (UV–vis) and four-probe measurements. FT-IR spectra confirmed that PANI was covalently bonded to MWCNTs. TEM images revealed the presence of Au or Ag nanoparticles finely dispersed in the composites with a size of <15 nm. XRD analysis revealed the presence of strong interactions between the metal nanoparticles and MWCNTs-f-PANI, where the metal particles were present in a phase-pure crystalline state with face centered cubic (fcc) structure. The room temperature electrical conductivity of the MWNCTs-f-PANI/Au or Ag composites was 4.8–5.0 S/cm, respectively, which was much higher than that of CNTs-f-PANI (0.18 S/cm) or pure PANI (2.5 × 10^?3 S/cm). A plausible mechanism for the formation of nanocomposites is presented. We expect that the new synthesis strategy reported here will be applicable for the synthesis of other hybrid CNTs–polymer/metal nanocomposites with diverse functionalities. This new type of hybrid nanocomposite material may have numerous applications in nanotechnology, gas sensing, and catalysis.     

Electrical behavior of conducting polymer based ‘polymeric–inorganic’ nanocomposite: Polyaniline and polypyrrole zirconium titanium phosphate

Composites are 21st century material used to meet the demand of improved materials and possess a combination of several desirable properties. Present study focussed on the conducting behavior of ‘polymeric–inorganic’ nanocomposite of conducting polymer polyaniline and polypyrrole. ‘Polymeric–inorganic’ nanocomposite cation-exchangers, i.e., polyaniline zirconium titanium phosphate (PANI-ZTP) and polypyrrole zirconium titanium phosphate (PPy-ZTP), were synthesized via sol–gel mixing of electrical conducting polymers into the matrices of inorganic precipitate of zirconium titanium phosphate (ZTP) having excellent ion exchange properties. The proposed nanocomposite possessed DC electrical conductivity in the semi-conducting range, i.e., 10^?5–10^?3 S cm^?1. The stability in terms of DC electrical conductivity retention was also studied in an oxidative environment by two slightly different techniques viz. isothermal and cyclic techniques. The DC electrical conductivity of composite material was found stable upto 110 °C under ambient conditions.     

Polyurethane latex modified with polyaniline

The strategy of the modification of polyurethane latex with a conducting polymer, polyaniline, is proposed. It is based on the introduction of the polymer steric stabilizer to the latex. The stabilizer prevents the macroscopic precipitation of a conducting polymer during the polymerization. Polyaniline has been prepared by the oxidative polymerization of aniline in the presence of polyurethane latex with average particle size of 36 nm and poly(N-vinylpyrrolidone). Thus, modified latex produces an aqueous colloidal dispersion having the particle size 100–200 nm. The presence of poly(N-vinylpyrrolidone) was needed to obtain a colloid. In its absence, a polyaniline–polyurethane composite precipitated. The composite coatings obtained after their drying contained 5–18 wt.% polyaniline in a protonated emeraldine form, had the conductivity up to 10⁻² S cm⁻¹, and mechanical properties typical of elastomers.     

Thermomechanical properties of TiC particle-reinforced tungsten composites for high temperature applications

Tungsten and tungsten alloys are widely used in high temperature environments where arc ablation or mechanical deformation and damage are the main sources of materials failure. For high temperature critical applications in thermomechanical environments, however, the low strength limits the use of tungsten and tungsten alloys. Hence, new tungsten based materials with good high temperature thermomechanical properties need to be developed in order to extend the use of tungsten. TiC particle-reinforced tungsten based composites (TiC_p/W) were fabricated by hot pressing at 2000 °C, 20 MPa in a vacuum of 1.3×10⁻³ Pa. The composites were examined with respect to their thermophysical and mechanical properties at room temperature and at elevated temperature. Vickers hardness and elastic modulus increased with increasing TiC content from 0 to 40 vol.%. The highest flexural strength, 843 MPa, and the highest toughness, 10.1 MPa m^1/2, of the composites at room temperature were all obtained when 20 vol.% TiC particle were added. As the test temperature rose, the flexural strength of the TiC_p/W composites firstly increased and then decreased, except in the monolithic tungsten. The highest strength of 1155 MPa was measured at 1000 °C in the composite containing 30 vol.% TiC particles. The strengthening effect of TiC particles on the tungsten matrix is more significant at high temperatures. With the addition of TiC particles, the thermal conduction of tungsten composites was drastically decreased from 153 W m⁻¹ K⁻¹ for monolithic W to 27.9 W m⁻¹ K⁻¹ for 40 vol.% TiC_p/W composites, and the thermal expansion was also increased. The new composites are successfully used to make high temperature grips and moulds.     

Self-assembled polyaniline nanotubes and nanoribbons/titanium dioxide nanocomposites

Self-assembled polyaniline (PANI) nanotubes, accompanied with nanoribbons, were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous medium, in the presence of colloidal titanium dioxide (TiO₂) nanoparticles of 4.5 nm size, without added acid. The morphology, structure, and physicochemical properties of the PANI/TiO₂ nanocomposites, prepared at various initial aniline/TiO₂ mole ratios, were studied by scanning (SEM) and transmission (TEM) electron microscopies, FTIR, Raman and inductively coupled plasma optical emission (ICP-OES) spectroscopies, elemental analysis, X-ray powder diffraction (XRPD), conductivity measurements, and thermogravimetric analysis (TGA). The electrical conductivity of PANI/TiO₂ nanocomposites increases in the range 3.8 × 10^?4 to 1.1 × 10^?3 S cm^?1 by increasing aniline/TiO₂ mole ratio from 1 to 10. The morphology of PANI/TiO₂ nanocomposites significantly depends on the initial aniline/TiO₂ mole ratio. In the morphology of the nanocomposite synthesized using aniline/TiO₂ mole ratio 10, nanotubes accompanied with nanosheets prevail. The nanocomposite synthesized at aniline/TiO₂ mole ratio 5 consists of the network of nanotubes (an outer diameter 30–40 nm, an inner diameter 4–7 nm) and nanorods (diameter 50–90 nm), accompanied with nanoribbons (a thickness, width, and length in the range of 50–70 nm, 160–350 nm, and ～1–3 μm, respectively). The PANI/TiO₂ nanocomposite synthesized at aniline/TiO₂ mole ratio 2 contains polyhedral submicrometre particles accompanied with nanotubes, while the nanocomposite prepared at aniline/TiO₂ mole ratio 1 consists of agglomerated nanofibers, submicrometre and nanoparticles. The presence of emeraldine salt form of PANI, linear and branched PANI chains, and phenazine units in PANI/TiO₂ nanocomposites was proved by FTIR and Raman spectroscopies. The improved thermal stability of PANI matrix in all PANI/TiO₂ nanocomposites was observed.     

Understanding the mechanical reinforcement of uniformly dispersed multiwalled carbon nanotubes in alumino-borosilicate glass ceramic

The improvement of mechanical properties of carbon nanotube–reinforced polycrystalline ceramic or glass matrix composites was limited in earlier studies by the difficulties in producing a good dispersion of carbon nanotubes. Additionally, a proper understanding of the reinforcing mechanisms, if any, affecting the mechanical properties of ceramics containing carbon nanotubes is still lacking. We report here the effects of a good dispersion of as much as 10 wt.% multiwalled carbon nanotubes (MWCNTs) on the mechanical properties of dense alumino-borosilicate glass ceramics (ABS) prepared by an ultrasonication-assisted sol–gel technique followed by hot pressing (950 °C; 2 h; Ar atmosphere). The fracture toughness and flexural strength of the nanocomposites increased with increasing MWCNT content up to 10 wt.%. The ABS–10 wt.% MWCNT nanocomposite possessed nearly double the strength of the unreinforced ABS, accompanied by ～150% improvement in fracture toughness. However, a further increase in MWCNT content to 15 wt.% resulted in a modest deterioration of the mechanical properties due to agglomeration of the MWCNTs. The carbon nanotubes have been observed to bridge crack openings of the order of ～100 nm and the experimental evidence, along with theoretical analysis, showed that crack bridging provided the major contribution towards the improvement in fracture toughness. Debonding between the MWCNTs and the matrix appeared to occur in the matrix, away from the actual interface. However, the absence of significant pull-out of broken sections of the MWCNTs during fracture, due to failure of the bridging CNTs being predominantly at the crack plane, indicates that further toughening may be available if this mechanism can be activated.     

Microstructure and dynamic mechanical properties of tungsten-based alloys in the form of extruded rods via microwave heating

The dynamic mechanical properties of 93W–4.9Ni–2.1Fe alloys in the form of extruded rods sintered by microwave heating were investigated under dynamic compression using a split Hopkinson Pressure Bar. The microstructure and microhardness values of the sintered specimens after dynamic compression were analyzed and tested. The results show that the deformation amount and microhardness of specimens increase with increasing strain rate. When the strain rate is 3000 S^− 1, the deformation amount is increased to the maximum value of 59.8%, and the microhardness values of the tungsten grains and the matrix phase are also promoted to the maximum values of 7.66 and 6.92 Gpa, respectively. The formation of cracks during compressive deformation initiates before the appearance of the adiabatic shear bands. As the strain rate increases, cracks initiating at the edge of specimens gradually propagate to the bulk alloy, and the adiabatic shear band is observed at about 45° to the loading direction under the strain rate of 3000 S^− 1. These findings suggest that tungsten-based alloys extruded rods sintered by microwave heating would be an ideal material with excellent self-sharpening and penetration performance for penetrators.     

Preparation and properties of conducting composites of polypyrrole and porous cross-linked polystyrene with and without supercritical carbon dioxide

Composites of polypyrrole (PPy) and porous cross-linked polystyrene (PCPS) were prepared using a two-step batch method proposed by Ruckenstein and Park. However, the solvent employed by Ruckenstein and Park (methanol) in the polymerization step of their method was replaced with supercritical CO₂. For comparison purposes, PPy/PCPS composites were also prepared using no solvent in the polymerization step. Conductivities as high as 10⁻² S cm⁻¹ were obtained, with or without the use of supercritical CO₂. Uniformity of conductivity was determined via surface and bulk conductivity measurements, as well as by a new volume conductivity measurement that provides a measure of spatial (three-dimensional) distribution of the conducting component in the composite.The conductivity of composites prepared with or without the use of supercritical CO₂ conformed to the same percolation behavior with respect to the amount of PPy formed. The percolation threshold in all cases was as low as 4 wt.%. The mechanical strength of the composites was found to be about the same as that of the host PCPS, as was the thermal stability. Therefore, the conductive component did not appear to adversely affect these properties of the host. Finally, the temperature behavior of the conductivity could be correlated with Mott's variable-range hopping (VRH) model for three-dimensional electronic transport.     

Characterization of mechanically alloyed nanocomposites in TiO2–B2O3–Mg–C quaternary system

The influence of the simultaneous presence of magnesium and graphite on mechanosynthesis of various nanocomposite powders in TiO₂–B₂O₃–Mg–C quaternary system was investigated. A mixture of boron oxide and titanium dioxide powders along with different amounts of magnesium and graphite was milled using a high-energy planetary ball mill to provide necessary conditions for the occurrence of a mechanically induced self-sustaining reaction (MSR). In the absence of C (100 wt.% Mg), TiB₂ nanopowder was formed as a result of combustion reaction after 34 min of milling. In the presence of both Mg and C, the mechanochemical reaction was completed after different milling times depending on the weight fraction of the reducing agents in the powder mixture. In the presence of x wt.% Mg–y wt.% C (x = 85 and 90; y = 100 − x), the mechanosynthesized composites contained TiB₂ and TiC as major compounds as well as MgO and Mg₃B₂O₆ as unwanted phases. With further increasing the graphite content to 30 wt.%, no mechanical activation was observed after 90 min of milling. The nanocomposite powders showed a bimodal particle size distribution characterized by the presence of several coarse particles (≈ 250 nm) along with finer particles with a mean size of about 75 nm. Formation mechanism of nanocomposites was explained through the analysis of the relevant sub-reactions.     

Preparation and ablation properties of Hf(Ta)C co-deposition coating for carbon/carbon composites

Continuous, uniform Hf(Ta)C coating was co-deposited on carbon/carbon composites by chemical vapor deposition. The phase composition, microstructure and ablation properties of the Hf(Ta)C coating are investigated. Results show that the as-prepared coating is a biphasic coating consisting of HfC and HfTaC₂. The particle-stacked structure is effective to produce a crack free Hf(Ta)C coating and good adhesion between the coating and C/C composites. The Hf(Ta)C coating can effectively protect C/C composites from ablation. After 60 s ablation, the mass and linear ablation rates of coated sample are 0.01 ± 0.02 mg cm⁻² s⁻¹ and 0.46 ± 0.02 μm s⁻¹, respectively.     

Mechanical and tribological properties of electrically conductive SiC based cermets

Three different types of SiC based cermets with various content (30, 40, 50 wt.%) of electrically conductive TiNbC phase have been fabricated by hot-pressing without sintering additives. The effect of TiNbC content on the basic mechanical, electrical and tribological properties of SiC-TiNbC cermets was investigated. Tribological properties have been characterized by the ball-on-disc method at the ambient temperature and dry wear conditions with air humidity 35–40% at the load of 5–30 N, sliding distance of 500 m, with the static partner made from SiC. Corresponding wear rate was calculated and wear mechanisms were identified. Resulting materials were relatively hard, with increasing amount of TiNbC the hardness increased from 19.8 ± 1 GPa for 30 wt.% of TiNbC up to 25.4 ± 0.9 GPa at 50 wt.% of TiNbC. The fracture toughness values were independent on TiNbC phase and varied between 2.7 and 2.9 MPa.m^1/2. Similarly, Young's modulus increased from 354 GPa to 435 GPa. It was found that electrical conductivity of SiC cermets was rapidly improved with increased fraction of metallic phases and was three orders of magnitude higher at 30 wt.% TiNbC addition and around four order of magnitude higher at 50 wt.% of TiNbC metallic phase comparing to conventional semiconductive SiC ceramics with electrical conductivity ~ 10 Sm^− 1. Coefficient of friction (between 0.3 and 0.5) and wear resistance (10^− 6–10^− 7 mm³/Nm) were comparable with the wear resistant SiC materials.     

Microstructure and properties of intermetallic composite coatings fabricated by selective laser melting of Ti–SiC powder mixtures

Transition metal silicides and carbides are attractive advanced materials possessing unique combinations of physical and mechanical properties. However, conventional synthesis of bulk intermetallics is a challenging task because of their high melting point. In the present research, titanium carbides and silicides composites were fabricated on the titanium substrate by a selective laser melting (SLM) of Ti–(20,30,40 wt.%)SiC powder mixtures by an Ytterbium fiber laser with 1.075 μm wavelength, operating at 50 W power, with the laser scanning speed of 120 mm/s. Phase analysis of the fabricated coatings showed that the initial powders remelted and new multiphase structures containing TiC_x, Ti₅Si₃C_x, TiSi₂ and SiC phases in situ formed. Investigation of the microstructure revealed two main types of inhomogeneities in the composites, (i) SiC particles at the interlayer interfaces and, (ii) chemical segregation of the elements in the central areas of the tracks. It was suggested and experimentally proven that an increase in laser power to 80 W was an efficient way to improve the laser penetration depth and the mass transport in the liquid phase, and therefore, to fabricate more homogeneous composite. The SLM Ti–(20,30,40 wt.%)SiC composites demonstrated high hardness (11–17 GPa) and high abrasive wear resistance (3.99 × 10⁻⁷–9.51 × 10⁻⁷ g/Nm) properties, promising for the applications involving abrasive wear.     

Facile one-step route to polyaniline–silver nanocomposite particles and their application as a colored particulate emulsifier

Polyaniline–silver nanocomposites were synthesized in the form of colloidal particles by the facile one-step aqueous chemical oxidative dispersion polymerization of aniline using silver nitrate as an oxidant and poly(vinyl alcohol) as a colloidal stabilizer. Aniline monomer was oxidized by silver ions, yielding polyaniline and elemental Ag simultaneously. The synthesized nanocomposite particles were colloidally stable over 2 years and transmission electron microscopy studies indicated the production of spherical, plate and rod-shaped polyaniline–silver nanocomposite particles with a silver core–polyaniline shell morphology. The conductivity of a pressed pellet of the nanocomposite particles using the conventional four-point probe technique was 1.4 × 10^?2 S/cm at 25 °C. The nanocomposite particles behaved as a ‘colored’ particulate emulsifier for the stabilization of transparent oil-in-water emulsions.     

Effect of growth rate on microstructure and mechanical properties of directionally solidified multiphase intermetallic Ni–Al–Cr–Ta–Mo–Zr alloy

The effect of growth rate on microstructure and mechanical properties of directionally solidified (DS) multiphase intermetallic alloy with the chemical composition Ni–21.9Al–8.1Cr–4.2Ta–0.9Mo–0.3Zr (at.%) was studied. The DS ingots were prepared at constant growth rates V ranging from 5.56 × 10⁻⁶ to 1.18 × 10⁻⁴ ms⁻¹ and at a constant temperature gradient at the solid–liquid interface of G_L = 12 × 10³ K m⁻¹. Increasing growth rate increases volume fraction of dendrites and decreases primary dendritic arm spacing, mean diameter of α-Cr (Cr-based solid solution) and γ′(Ni₃Al) precipitates within the dendrites. Room-temperature compressive yield strength, ultimate compressive strength, hardness and microhardness of dendrites increase with increasing growth rate. All room-temperature tensile specimens show brittle fracture without yielding. The brittle-to-ductile transition temperature for tensile specimens is determined to be about 1148 K. Minimum creep rate is found to depend strongly on the applied stress and temperature according to the power law with a stress exponent of n = 7 and apparent activation energy for creep of Q_a = 401 kJ/mol.     

Laser doping of chromium as a double acceptor in silicon carbide with reduced crystalline damage and nearly all dopants in activated state

Chromium, a p-type dopant, has been incorporated into silicon carbide by laser doping. Secondary ion mass spectrometric data revealed enhanced solid solubility (2.29 × 10¹⁹ cm⁻³ in 6H–SiC and 1.42 × 19¹⁹ cm⁻³ in 4H–SiC), exceeding the equilibrium limit (3 × 10¹⁷ cm⁻³ in 6H–SiC above 2500 °C). The roughness, surface chemistry and crystalline integrity of the doped sample were examined by optical interferometry, energy dispersive X-ray spectrometry and transmission electron microscopy, respectively, and showed no crystalline disorder due to laser heating. Deep-level transient spectroscopy confirmed Cr as a deep-level acceptor with activation energies E_v + 0.80 eV in 4H–SiC and E_v + 0.45 eV in 6H–SiC. The Hall effect measurements showed that the hole concentration (1.942 × 10¹⁹ cm⁻³) is almost twice the average Cr concentration (1 × 10¹⁹ cm⁻³), confirming that almost all of the Cr atoms were completely activated to the double acceptor state by the laser-doping process without requiring any additional annealing step.     

Lithium surface protection by polyacetylene in situ polymerization

Direct acetylene polymerization at ambient temperature on a Li metal surface and polyolefin separator with Ziegler–Natta catalyst was developed. Thin conducting polyacetylene films with strong adhesion to Li or polyolefin surface was formed and studied by electrochemical methods. AC impedance measurements and charge/discharge tests were applied for prepared coin cells with LiCoO₂ as a cathode material in the presence of 1 M LiPF₆ in dimethyl carbonate, ethylene carbonate, propylene carbonate (5:3:2 vol) electrolyte. Three kinds of polyolefins were used to prepare composite separators with polyacetylene: polypropylene (PP), polyethylene (PE) and three-layer type: PP–PE–PP.The polyacetylene film thickness on Li metal or polyolefin separator was easily controlled by catalyst concentration and polymerization time. It was shown that high ionic conductivity (7.5 × 10⁻⁵ S cm⁻¹) might be achieved due to higher porosity of a polyethylene separator. Li–polyacetylene electrodes showed highest ionic conductivity and stability in charge/discharge tests.