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Solid polymer electrolytes (SPEs) have been recognized as a preferable alternative to liquid electrolytes for energy storage application. However, low conductivity of SPEs has restricted their application. This issue can be overcome by adding controlled amount of dopant salt to the SPEs. In this work, various concentration of ammonium thiocyanate (NH4SCN) salt was incorporated into dextran using solution cast technique in order to study the effect of NH4SCN on electrical properties, crystallite size, morphology and ionic conductivity. Results from Fourier-transform infrared (FTIR) analysis confirm the coordination of cation of salt at the OH and C-O-C groups of dextran. Deconvolution of the FTIR band between 2015 and 2090 cm−1 was performed to investigate the ion association and dissociation phenomena. It is confirmed that the ion mobility and diffusion are directly proportional to the ionic conductivity. Based on the electrochemical impedance spectroscopy (EIS) result, an optimum ionic conductivity of (3.18 ± 1.19) × 10−4 S cm−1 was achieved with the sample containing 40 wt.% salt concentration. The conductivity result can be clarified by the crystallite size obtained from X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM) images. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes were prepared using polymethyl methacrylate (PMMA), ethylene carbonate (EC), lithium trifluoroethane-sulfonate (LiTf), magnesium trifluoro-methanesulfonate (MgTf2). The ionic conductivity was measured at 30 °C as 6.17 × 10−6 and 1.83 × 10−4 S cm−1, respectively. The ionic mobility (μ), charge carrier diffusion coefficient (D) and the ion number density (n) of the samples have been calculated to understand the effect of these parameters on the ionic conductivity. The experimentally obtained values of Z r and Z i are compared with theoretical calculations. The PMMA-EC-MgTf2 sample exhibits higher dielectric constant compared to PMMA-EC-LiTf. The MgTf2 containing sample also exhibits a higher transference number. [ABSTRACT FROM AUTHOR]

Fe-based spincrossover (SCO) molecular complexes have shown to exhibit spincrossover behavior when subjected to stimuli such as heat, light and pressure. In a previous work, solutions of Fe-based spincrossover (SCO) molecular complexes with increasing ligand length, CnH2n+1NH2 (n = 12, 14, 16) of Fe(L12)2](BF4)2, [Fe(L14)2](BF4)2, and [Fe(L16)2](BF4)2, have shown to produce ultrahigh Seebeck coefficients when subjected to a temperature gradient. In this work, these three compounds are dissolved in dimethyl sulfoxide (DMSO) and subjected to temperature dependent Ultraviolet-visible (UV-vis) spectrometry. This optical characterization method was used to provide a correlation between the ligand length of the SCO complex and the bandgap energy measured. Subsequently, these findings were also triangulated with the effect of the ligand length on ionic conductivity and the Seebeck voltage. This work thus provides a systematic molecular understanding of the optical and electronic characteristics of SCO complexes, which paves the way for molecular design strategies in utilization of SCO for applications such as energy conversion and sensors. [ABSTRACT FROM AUTHOR]

A novel phase was fabricated using a liquid crystal medium, and its feasibility as an ion-conducting material was explored. The intermediate phase comprised a strong polar compound and a low-molecular-weight nematogen, which was insoluble in the compound. Nanoscale phase segregation occurred between the host nematogen and guest polar compound upon dispersing a small amount of the polar compound into the nematogen. This nano-segregated phase was characterized through polarized optical microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Furthermore, the ionic conductivity of the nano-segregated phase was qualitatively evaluated by voltage holding ratio measurements. [ABSTRACT FROM AUTHOR]

Poly(acrylamide-co-acrylic acid) (PAAm-PAA) based solid polymer electrolytes (SPEs) containing potassium iodide (KI) have been prepared. The complexation between PAAm-PAA and KI has been identified through the position changes at the asymmetric NH2 stretching and CH2 stretching; and the intensities changes at the amide (C = O, C-N) and carboxylate (COO-) bands using Fourier transform infrared (FTIR) spectroscopy. PAAm-PAA film exhibits a room temperature (RT) ionic conductivity of (8.8 ± 0.8) × 10−11 S·cm−1 which increases to maximum at (4.0 ± 0.5) × 10−7 S·cm−1 with 45 wt.% KI addition. The conductivity-temperature dependence studies of all samples followed the Arrhenius rule. [ABSTRACT FROM AUTHOR]

The formulation of a hybrid gel polymer electrolyte (HGPE) system comprising of polymethyl methacrylate (PMMA) and polylactic acid (PLA) as a hybrid host polymer doped with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) has been successfully prepared in this study with the introduction of an ionic liquid, namely 1-Ethyl-3-methylimidazolium chloride (EMIMCl). Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were used to investigate the structural features of HGPEs. The FTIR analysis revealed that the complexation changes the peak intensity at region C = O stretching, CH2 bending, and C-O stretching. Meanwhile, XRD showed that the addition of EMIMCl altered the HGPE properties and formed an amorphous structure. The prepared HGPE sample was examined for ionic conduction properties through electrical impedance spectroscopy (EIS). It shows that by adding an EMIMCl to the PMMA-PLA-LiTFSI HGPE has decreased the activation energy (Ea) and increased the ionic conductivity. The sample containing 15 wt.% has the lowest Ea value of 0.057 eV and the highest ionic conductivity at room temperature of 3.20 10−3 S cm−1. The itemperature dependence was studied in the temperature range from 303 K to 393 K, the HGPE systems were found to follow Arrhenius behavior. The effect of EMIMCl content had decreased the viscosity of HGPEs which led to the gel-like type behavior. The potential windows stability analysis revealed that the highest conducting sample was electrochemically stable up to 3.3 V versus Li/Li+, thus showing that the present electrolytes are promising to be applied as in Li-ions battery. [ABSTRACT FROM AUTHOR]

In this article, the complexation of methylcellulose (MC) with tri-potassium phosphate (K3PO4) is investigated using an ultrasonication-assisted solution cast process. X-ray diffraction (XRD) analysis indicates that varying concentrations of K3PO4 salt (7–35 wt.%) disrupt the crystalline segment of the MC host matrix. The considerable shift in the intensity and orientation of the Fourier transforms infrared spectroscopy (FTIR) transmittance bands indicate the establishment of a charge-transfer entanglement between the polymer host and the dispersed salt. The optimum sample (28 wt.%) exhibits a high ionic conductivity of 1.74 × 10−5 S cm−1, potential stability of 3.48 V, and a cation transference number (ti) of 0.945. These findings show the relevance of the developed SPEs for possible application in electrochemical devices. [ABSTRACT FROM AUTHOR]

In the present work, the transport properties and morphology through tunneling structures were investigated, where the rough In2S3 thin films are the interfaces of these structures. In2S3 thin films were doped experimentally with Copper (Cu) and their morphology was studied by using the atomic force microscopic images at different temperatures (30, 55, 70, and 85 ° C). The results show that conductivity of the samples is strongly influenced by Cu doping content at different temperatures. Also, the transmission probability and current density of these samples were investigated numerically. The results show the maximum scattering component of transmission probability at temperature 30 ° C , for In2S3 thin films and 70 ° C , for CuIn2S3 thin films. By the results, increasing of the [Cu/In] molar ratios will lead to an increase in the transmission probability and current density of these thin films. [ABSTRACT FROM AUTHOR]

Recently, considerable researches are conducted to develop promising polymer electrolytes for Li-ion batteries (LIBs). Herein, we prepared poly(lithium acrylate) (PAALi)-based composite polymer electrolytes (CPEs) containing alumina (Al2O3) nanoparticles. The addition of inorganic nanoparticles into the PAALi matrix can not only improve CPE's ionic conductivity ( σ D C ∼ 1.3 × 10 − 2 S / cm at 303 K), but also enhance CPE's mechanical properties due to the nanoparticles acting as cross-linkers between the PAALi chains. We systematically investigated the influences of inorganic nanoparticle types (pure alumina vs. vinyl functionalized alumina) and contents on ionic conduction and mechanical properties of PAALi-based CPEs. [ABSTRACT FROM AUTHOR]

Recently, solid polymer electrolytes (SPEs) are of great current interest as substitutes to conventional liquid type electrolytes. Although the SPEs significantly alleviate the safety issues of the lithium-ion batteries based on conventional liquid electrolytes, they intrinsically exhibit low ion conductivity. In this study, a bicontinuous solid polymer electrolyte containing polyacrylonitrile (PAN) membrane and a mixture of succinonitrile (SN) and lithium bis(trifluoromethanesulfonyl)imide was prepared with different molarities of the lithium salt. Porous PAN membrane was fabricated via a thermally induced phase separation method (TIPS). The PAN-based SPE exhibited the maximum ionic conductivity of ∼5.0 × 10−3 S/cm at the salt molarity of 1.0 M. [ABSTRACT FROM AUTHOR]

The glass of lithium-sodium tetragermanate LiNaGe4O9 was prepared by fast quenching the melt. The glass was devitrified on heating under the control of differential scanning calorimetry. It was shown that the glass crystallized through a single stage. Electrical properties were measured on heating in the interval including the characteristic temperatures of the glass devitrification. It was shown that electrical conductivity increased on approaching glass transition temperature Tg from below and sharply dropped down after the glass crystallization. Charge transfer in LiNaGe4O9 glass and polycrystal was attributed to Li ions motion. The data obtained can be used for the preparation of the nanometer sized LiNaGe4O9 glass ceramics with increased ionic conductivity. [ABSTRACT FROM AUTHOR]

The glass of lithium-sodium tetragermanate LiNaGe4O9 was prepared by fast quenching the melt. The glass was devitrified on heating under the control of differential scanning calorimetry. It was shown that the glass crystallized through a single stage. Electrical properties were measured on heating in the interval including the characteristic temperatures of the glass devitrification. It was shown that electrical conductivity increased on approaching glass transition temperature Tg from below and sharply dropped down after the glass crystallization. Charge transfer in LiNaGe4O9 glass and polycrystal was attributed to Li ions motion. The data obtained can be used for the preparation of the nanometer sized LiNaGe4O9 glass ceramics with increased ionic conductivity. [ABSTRACT FROM AUTHOR]

Triblock copolymers comprising chemically complementary poly(ethylene oxide)/polyacrylamide (TBC) and their partially hydrolyzed derivative (TBChydr) were investigated as possible ion-conducting membranes for Li-ion batteries (LBs), dye-sensitized solar cells (DSSCs) and fuel cells (PEFCs). Two TBC samples consisting PEO blocks of variable block length (MnPEO = 6·104 and 3.5·104 kDa) were synthesized and used for these purpose. It was noticed that ionic conductivity of TBC membranes increases with PEO block lengthening from 6.2·10−11 to 3.2·10−9 S⋅cm−1. The introduction of additional ionic groups -COOH in polyacrylamide block of TBC has a positive effect on the conductive characteristics of copolymer membranes. The ionic conductivity of TBC membranes filled with LiPF6 increases with increasing of salt content. [ABSTRACT FROM AUTHOR]

Incorporation of magnesium oxide nano particles (MgONPs) in a nematic liquid crystal display material namely 4-pentyl-4'-cyanobiphenyl (5CB) have been analyzed by differential scanning calorimeter, polarizing light microscopy and dielectric spectroscopy. MgONPs have been dispersed in two different concentrations in pure 5CB viz. 0.2 and 0.6 wt%. It has been experimentally noticed that with the increase of MgONPs concentrations in 5CB, the nematic to isotropic transition temperatures decreases and dielectric anisotropy increases. Relaxation frequency of an observed relaxation mode corresponding to molecular rotation about the short axis is almost unchanged after dispersion of MgONPs. The ionic conductivity has increased by approximately one order of magnitude for 0.6 wt% MgONPs and decreased for 0.2 wt%. [ABSTRACT FROM AUTHOR]

The chemical cross-linking of epoxy resin has been known as an imperative way to improve the mechanical strength and thermal stability of solid polymer electrolytes (SPEs). Herein, we prepare flexible epoxy-based SPEs with high ion conductivity for electrochemical devices via ring-opening polymerization. A diglycidyl ether of bisphenol-A (DGEBA) epoxy resin was selected as the mechanical supporting SPE matrix. The high flexibility of SPEs can be obtained by adding poly(ethylene glycol) diglycidyl ether (PEGDE) plasticizer to the epoxy resin. Furthermore, the incorporation of electrolyte mixture of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salts and 1-butyl-3 methylimidazolium bis(trifluorosulfonyl)imide (BMIM-TFSI) ionic liquids allows for boosting ionic conductivity of the epoxy-based SPEs. Consequently, the high room temperature ionic conductivity ∼2.4 × 10−3 S/cm was achieved in the SPE containing 30 wt% of the epoxy and 70 wt% of the electrolyte mixture. [ABSTRACT FROM AUTHOR]

Recently, research on solid polymer electrolytes (SPEs) for lithium-ion batteries (LIBs) has been actively carried out as an alternative to conventional liquid electrolytes that present safety issues such as flammability and explosion. However, the SPEs show relatively low ion conductivity, compared to the liquid electrolytes. In this study, a poly(vinylidene difluoride) (PVDF)-based SPE was prepared by introducing two different electrolytes; one is weak-binding lithium bis(trifluoromethane)sulfonimide (LiTFSI) salt mixture with solvating plastic crystal succinonitrile (SN) and the other is lithium bis(fluorosulfonyl)imide (LiFSI) salts. Among the SPEs studied, the PVDF/LiFSI-containing SPE membrane exhibited the highest room temperature ion conductivity of 1 x 10−3 S/cm, characterized by electrochemical impedance spectroscopy (EIS). [ABSTRACT FROM AUTHOR]

The influence of Ag7GeS5I nanoparticles on dielectric properties of planar-oriented 6CB liquid crystal was investigated at 293 K within the frequency range from 6 to 106 Hz. The concentration of nanoparticles varied between 0 to 0.1 wt.%. The obtained results were compared with the influence of the same concentrations of Сu7GeS5I nanoparticles. It was shown that the Сu7GeS5I nanoparticles influence the conductivity of the liquid crystal significantly less than the Ag7GeS5I nanoparticles. [ABSTRACT FROM AUTHOR]

Electrical conductivity σ was studied in single- and polycrystalline lithium heptagermanate Li2Ge7O15 doped with Al. In Li2Ge7O15:Al single crystal conductivity demonstrated strong anisotropy. As compared with pure crystal, doping significantly increased conductivity along the structural channels parallel to a and c axes. The doping effect was interpreted by supposing that Al3+ substituted for Ge4+ hosts. Li interstitials (ALi) were considered as the defects compensating charge imbalance introduced by the impurity. Heterovalent substitution Al3+(Ge4+) noticeably increased concentration of ALi which were mobile enough and contributed to conductivity. Influence of Al doping on σ was compared for Li2Ge7O15 single crystal and polycrystal. [ABSTRACT FROM AUTHOR]

Solution casting technique has been used to prepared chitosan-based polymer electrolyte films. The polymer electrolyte (PE) film containing 55 wt.% of biopolymer chitosan, 45 wt.% of NH4I salt and 80 wt.% of 1-butyl-3-methylimidazolium iodide (BMII) displayed the highest room temperature ionic conductivity of 3.02 × 10−4 S cm−1. The interaction between components in the biopolymer electrolyte has been optically investigated. The configuration of indium tin-oxide (ITO)/TiO2/Ru-complex (N3) dye/biopolymer electrolyte/Pt/ITO dye-sensitized solar cells (DSSCs) were fabricated. DSSC with chitosan-based PE consist of 80 wt.% BMII exhibited the highest efficiency of 1.2%. [ABSTRACT FROM AUTHOR]

Influence of fullerenes C60 on the threshold voltage, dielectric, and conductivity properties of smectic A liquid crystal 4-nitrophenyl-4′-decyloxybenzoic acid is investigated. It is shown that the transverse component of the real part of dielectric permittivity increases at the additive of fullerenes while the longitudinal component decreases. At this case, a maximum of dielectric absorption shifts to the high-frequency region. Conductivity increases at low frequencies and decreases at the high ones. Experimental results are explained on the base of the Maier-Meier theory for anisotropic liquids and also participation of fullerenes in ionic conductivity of liquid crystal. [ABSTRACT FROM AUTHOR]

Recently, extensive efforts have focused on the development of solid polymer electrolytes (SPEs) requiring high mechanical performance without sacrificing ion conductivity. To develop such a SPE, we incorporate robust silica mesoporous particles (SMP) into the epoxy-based SPEs, and increasing the SMP content raises the glass transition temperature of the SPEs. This enables to increase the mechanical properties of the SPEs, supported by the microstructural investigation showing a highly compact structure. Ionic conductivities of these SPEs follow Vogel temperature dependence, and increasing the silica nanoparticle content leads to a slight decrease in the conductivity, consistent with the dielectric response investigation. [ABSTRACT FROM AUTHOR]

DNA-DODA with 7 to 11 wt% of either LiClO4or LiI/I2ionic conducting membranes were synthesized, characterized, and applied in small TiO2-dye sensitized solar cells (DSSC). The best ionic conductivity values of 2.9 × 10−4and 2.3 × 10−5S/cm at 25°C were obtained for samples with 10 wt% of LiClO4and LiI/I2, respectively. The samples displayed Arrhenius behavior of ionic conductivity as a function of temperature and activation energies of 32.7 and 37.1 kJ/mol. TGA showed ∼10% weight loss up to 120°C and a start of degradation process at ∼200°C. The membranes with 10 wt% of LiClO4and 9 and 10 wt% of LiI/I2applied in DSSCs revealed solar efficiencies of 0.21, 0.37, and 0.51, respectively. [ABSTRACT FROM PUBLISHER]

New polymer electrolytes (PEs), potentially interesting for solid-state electrochemical devices applications, were synthesized by a solvent casting method using pectin and ionic liquid (IL)N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ([N1 1 1 2(OH)] [NTf2]. The resulting electrolytes besides being moderately homogenous and thermally stable below 155°C, they also exhibited good mechanical properties. The SPE membranes were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and complex impedance spectroscopy. [ABSTRACT FROM PUBLISHER]

The research in the field of electronic and photonic devices based on ordered organic semiconducting materials has been boosted by the development of new multifunctional materials. The order characterizing liquid crystals has been exploited for improving charge mobility performances. However, while in the last decade much effort has been addressed to the synthesis of hole-conducting materials (p-type), less attention has been paid on the development of electron-conducting ones (n-type). Here we show the bulk multifunctional properties of a π-conjugated thienoviologen ionic liquid crystal which exhibits strong electron acceptor character. Notably, the combination of its optical properties with high ionic conductivities and fast intermolecular electron transport, leads to unique bulk electrochromic functions. [ABSTRACT FROM AUTHOR]

Recently, light emitting electrochemical cells (LECs) have received considerable attention for their application in display and lighting applications. In this manuscript we put forward a study of cationic iridium complex and ionic conductor blend as the active layer of light emitting electrochemical cells. Tetrabutylammonium triflate functions as an ionic conductor. We have synthesized iridium metal complex using phenanthroline based ancillary ligands and studied light emitting properties of the devices in pristine as well as ionic conductor blends. Current density, luminescence plots were well studied against applied bias and on comparison, the devices with ionic liquids showed better performance. [ABSTRACT FROM AUTHOR]

The electrical impedance response of six nematic liquid crystals samples is analyzed by means of an extension of the Poisson-Nernst-Planck diffusional model. This formulation includes fractional derivatives of distributed order governing the behavior of the bulk density of mobile charges, whose solutions are subjected to integro-differential equations accounting for the boundary conditions. The role of the intrinsic surface lengths involved in the adsorption-desorption phenomena at the electrodes is emphasized, in order to analyze the frequency dependence of the real and imaginary parts of the electrical impedance experimentally obtained. [ABSTRACT FROM AUTHOR]

A hole formed in photo-excited dye molecule under illumination is transferred to cathode with iodine ion in electrolyte solution in the dye-sensitized solar cell developed by M. Grätzel and the conductivity of the iodine ion affects conversion efficiency of the cell. In this work, effect of the polymeric p-type semiconductor on the hole transferability is investigated. PEDOT:PSS and P3HT were used as the p-type semiconductors. Dye-sensitized solar cells were composed of aluminium plate, Nb-doped TiO2 layer adsorbed with TCNQ, the electrolyte solution containing iodine ions, and ITO glass plate. In a solid-type cell substituted the electrolyte solution with the p-type semiconductor, photocurrent was not generated. The photocurrent was generated in the solar cell by introducing the electrolyte solution containing iodine ions between the ITO glass and the p-type semiconductor formed on the dye-adsorbed Nb-doped-TiO2 layer or between the dye-adsorbed Nb-doped-TiO2 layer and the p-type semiconductor formed on the ITO glass. The conversion efficiency increased with the introduction of the p-type semiconductor such as PEDOT:PSS, compared only with the electrolyte solution. The p-type semiconductor containing iodine ions promote the hole transfer of iodine ion, compared with that in the electrolyte solution. [ABSTRACT FROM PUBLISHER]

The present study investigates gel polymer electrolytes (GPEs) based on sodium alginate plasticized with glycerol containing either CH3COOH or LiClO4. The membranes showed ionic conductivity results of 3.1 × 10−4 S/cm for the samples with LiClO4 and 8.7 × 10−5 S/cm for the samples with CH3COOH at room temperature. The samples also showed thermal stability up to 160°C, transparency of up to 90%, surface uniformity and adhesion to glass and steel. Moreover, Dynamic Mechanical Analysis revealed two relaxations for both samples and the Ea values were between 18 and 36 kJ/mol. All the results obtained indicate that alginate-based GPEs can be used as electrolytes in electrochemical devices. [ABSTRACT FROM PUBLISHER]

Gellan-based polymer electrolytes (PEs), doped with lithium iodide (LiI), were prepared and their electrical properties were characterized. The samples are thermally stable up to 234°C and exhibit ionic conductivity of 3.8 × 10−4 S/cm at room temperature for the sample doped with 40 wt% of LiI. Addition of 10 wt% of glycerol promotes an increase of the ionic conductivity to 1.5 × 10−3 S/cm, which remains stable up to 100°C. The activation energies of 2.4 to 12.4 kJ/mol were derived from the Arrhenius model. The repeated ionic conductivity measurements as a function of temperature show that these membranes can be reversibly used between the room temperature and 100°C. [ABSTRACT FROM PUBLISHER]

Gel Polymer Electrolytes (GPE) based on agar and containing LiClO4 have been prepared, characterized and applied to electrochromic devices. The ionic conductivity revealed the best result of 6.5 × 10−5 S/cm for the sample with 17 wt.% of LiClO4, which increased to 5.4 × 10−4 S/cm at 72°C. The GPE have been used in electrochromic devices (ECD) with K-glass/WO3/GPE/CeO2-TiO2/K-glass configuration. The ECD changed transmittance values up to 30% between the colored and transparent states. The charge density measurements revealed an increase of 5.5 to 7.5 mC/cm2 from the first to 500th cycles and then a decrease to 4.4 mC/cm2 during the next 4500 cycles. Coloration efficiency (η) of 25 cm2/C was obtained. [ABSTRACT FROM PUBLISHER]

Ionic conducting membranes of gelatin plasticized with glycerol and containing LiI/I2 have been obtained and characterized by X-ray diffraction measurements, UV-Vis-NIR spectroscopy, thermal analysis and impedance spectroscopy. The transparent (80–90% in the visible range) membranes showed ionic conductivity value of 5 × 10−5 S/cm at room temperature, which increased to 3 × 10−3 S/cm at 80°C. All the ionic conductivity measurements as a function of temperature showed VTF dependence and activation energy of 8 kJ/mol. These samples also showed low glass transition temperature of −76°C. Moreover the samples were predominantly amorphous. The membranes applied to small electrochromic devices showed 20% of color change from colored to bleached states during more than 70 cronoamperometric cycles. [ABSTRACT FROM PUBLISHER]

Plasticized natural macromolecules-based polymer electrolyte samples were prepared and characterized. The plasticization of chitosonium acetate with glycerol increased the ionic conductivity value from 3.0 × 10−7 S/cm to 1.1 × 10−5 S/cm. The conductivity temperature relationship of the samples exhibits either VTF or Arrhenius type depending on the glycerol concentration in the sample. The dielectric studies evidencing the relaxation process in the plasticized sample at low frequency region are due to the electric polarization effect. Moreover, the samples were transparent in the Vis region, showed thermal stability up to 160°C and good surface uniformity. [ABSTRACT FROM PUBLISHER]

A promising alternative of multi-layered devices showing electrochromic properties results from the design of a self-supported semi-interpenetrating polymer network (semi-IPN) including an electronic conductive polymer (ECP). The formation of the ECP in the network has already been described by oxidative polymerization using iron trichloride as an oxidant and leading to conducting semi-IPN with mixed electronic and ionic conductivities as well as convenient mechanical properties. This work relates to the elaboration of such semi-IPN using a PEO/NBR (Nitrile Butadiene Rubber) IPN in which a linear poly (3, 4-ethylenedioxythiophene) (PEDOT) is formed symmetrically and selectively as thin layers on the two sides of the film matrix. PEO/NBR/PEDOT semi-IPNs lead to interesting optical reflective properties in the IR between 0.8 and 25 μm. Reflectance contrasts up to 35% are observed when, after swelling in an ionic liquid, a low voltage is applied between the two sides of the film. The PEO/NBR IPN as a thin film possesses both a good flexibility and a good resistance against thermal ageing compared with a single PEO network previously employed. Moreover, the combination of NBR and PEO in an IPN leads to materials possessing a good ionic conductivity at 25°C. Finally, NBR/PEO/PEDOT semi-IPNs allow observing comparable reflectance contrast in the IR range than those previously shown by PEO/PEDOT semi-IPNs. [ABSTRACT FROM PUBLISHER]

Lithium is known to form complexes with organic compounds including polymers which have different kinds of bonding. Regular polymers as poly(ethylene oxide) can form crystalline complexes with ionic bonds with Li. In this work, statistical copolymers acrylonitrile - high methacrylates are synthesized, and their nanocomposites with a lithium salt are prepared. Their dielectric characteristics and ionic conductivity are studied. The results describe interactions between Li and copolymers which can be explained by the lithium bonding in systems. [ABSTRACT FROM AUTHOR]

Photoelectrical and current transient properties of TlBr were investigated in the temperature region from -20°C up to +20°C, in which effect of the ionic conductivity changes significantly. Non-monotonous conductivity change with temperature was identified, demonstrating mobility-related maximum superimposed on a band-to-band generation conductivity growth. This maximum could be caused by the recharge of the scattering centre at about 1.65 eV. Presence of such centre was confirmed by the photocurrent spectra. From spectral dependencies defect-related transitions at 0.55; 0.83, 1.1; 1.32 and 1.65 eV were identified, being dependent on sample prehistory, i.e., its excitation by light and/or voltage. The transient photocurrent kinetics have demonstrated a complex behaviour that could be explained by the combined influence of electron generation/recombination processes superimposed upon the effect of ionic conductivity. The results indicate that ionic conductivity can take place also at -20°C, though its influence is less because of the thermally activated character. [ABSTRACT FROM AUTHOR]

Natural polymers are a very interesting matrix to obtain solid polymeric electrolytes (SPE). The principal advantage comes from their particularly interesting biodegradation properties due to the natural origin and also very low cost and good physical and chemical properties. These polymers contain heteroatoms in their structure and for this reason can interact with protons or lithium ions leading to the ionic conduction. Among different natural polymers, starch-based SPEs show good opto-electrochemical characteristics and can be applied to electrochemical devices. This work presents the results of starch and starch derivatives-based electrolytes, which were characterized by impedance spectroscopy and thermal analysis. The ionic conductivity results obtained for these SPEs varied from 10-6 S/cm to 10-4 S/cm at room temperature, depending on the sample, and increased following Arrhenius model. The samples showed good stability up to 200°C evidenced by thermal analysis (TGA). Good conductivity results combined with transparency and good adhesion to the electrodes have shown that starch-based SPEs are very promising materials to be used as solid electrolytes in electrochromic devices. [ABSTRACT FROM AUTHOR]

Photoelectrical and current transient properties of TlBr were investigated in the temperature region from - 20 C up to + 20 C, in which the effect of ionic conductivity changes significantly. The thermal activation energy value of conductivity of about 0.78 eV could stand for several mechanisms, e.g., electronic and ionic conductivity. From the spectral dependencies of photocurrent several defect-related maxima in the region between 1 and 2.5 eV were identified, being dependent on sample prehistory, i.e., its excitation by light and/or voltage. The transient photocurrent kinetics had demonstrated a complex behaviour that could be explained by the combined influence of electron generation/recombination processes superimposed upon the effect of ionic conductivity. The results indicate that ionic conductivity can take place also at - 20 C, though its influence is less because of the thermally activated character. [ABSTRACT FROM AUTHOR]

With a view to enhancing the ionic conductivity via the control of chain mobility of solid polymer electrolyte(SPE)based on poly(ether urethane)(PEU), polyurethane(PU)matrix containing polyethylene glycol(PEG)and polypropylene glycol(PPG)randomly distributed within matrix was synthesized from the simultaneous polymerization of PEG-PU and PPG-PU prepolymers. The efficacy of PEG-co-PPG-PU complexed with LiClO 4 salt as a SPE is discussed and compared with that of PEG-PU/LiClO 4 . [ABSTRACT FROM AUTHOR]

Temperature dependence of dielectric behavior of antiferroelectric liquid crystal, MHPB(H)PBC, has been investigated in the frequency range of 1  Hz to 10  MHz. The experimental results have been analyzed using a generalized Cole–Cole expression. There is mainly one relaxation mechanism in SmA∗ phase, which behaves as soft mode. Two dielectric relaxation processes have been observed in SmCA∗ phase, one at about 50  kHz and the other at about 400  kHz. Dielectric strengths of both modes remain constant throughout the SmCA∗ phase, while relaxation frequencies of both modes decrease with decrease in temperature. These two observed modes have been assigned to the in-phase and antiphase azimuthal fluctuations of the director of molecules in the antitilt pairs. [ABSTRACT FROM AUTHOR]

Oligo(ethylene oxide) chains were introduced into the phenyl ring of the poly-(phenylene vinylene) (PPV) derivatives to obtain electronic and ionic conductive liquid crystalline PPV derivatives. Thermal decomposition of all PPV derivatives occurred before isotropic melt. A typical texture of the liquid crystalline phase was not shown but birefringence was observed below the thermal decomposition temperature. Exhibition of a smectic phase for the polymers having triethylene or tetraethylene oxide chains was supported by X-ray measurements. Electronic conductivity of the PPV derivatives doped with I2 and ionic conductivity of the mixture of these polymers and LiClO4 were also discussed. [ABSTRACT FROM AUTHOR]

The synthesis and characterization is reported of a novel discotic side group polymer based on a predominantly poly(ethylene oxide) backbone to which are attached triphenylene-based mesogenic groups via flexible spacers. The thermal and mechanical behavior of this polymer and its complex with lithium perchlorate are compared. The addition of salt increased both the glass transition temperature and clearing point of the host polymer. The temperature dependence of the ionic conductivity of the polymer-salt complex is reported and reveals that ionic conduction can occur in essentially solid-like liquid crystal polymer electrolytes. Ion transport in this material presumably involves assistance from local segmental motions of the backbone but does not rely upon long range cooperative motions. [ABSTRACT FROM AUTHOR]