Search

A composite polymer electrolyte system based on PEMA/PVAc/LiClO4/EC with different wt% of nano filler TiO2 was prepared by solution casting technique.The structural investigations of the prepared polymer electrolyte membranes were carried out using X-ray diffraction and Fourier Transform infrared spectroscopictechniques. The electrical measurements were performed at various temperatures 303–363 K using ac impedance technique. The maximum room temperature ionic conductivity of 2.745 × 10 −3  S/cm was obtained for the polymer electrolyte membrane with 10 wt% TiO2. The temperature dependent ionic conductivity plot exhibited VTF behaviour. The porous nature of the membranes was verified from the SEM and AFM images. The thermal investigations performed on the samples by DSC technique displayed prominent endothermic peaks which revealed that the samples with the incorporation of filler had undergone a transition tothe amorphous phase at lower temperatures. The thermal stability of the film (F3) of maximum ionicconductivity was found to be 260 °C by means of TG/DTA analysis. The wide electrochemical stability window of –2.1 V to +2.1 V and the cyclability & reversibility of the maximum ion conducting sample at ambient temperature were confirmed by carrying out the electrochemical characterizations such as linear sweep voltammetry and cyclic voltammetry respectively. [ABSTRACT FROM AUTHOR]

The polymer electrolytes composed of poly(vinylidene fluoride-co-hexafluoropropylene) with various concentration of ammonium thiocyanate salt have been prepared by solution casting technique. The complex formation between polymer and dissociated salt has been confirmed by X-ray diffraction analysis and Fourier transform infrared spectroscopy. The highest conductivity has been found to be 6.5 × 10−3 S cm−1at 343 K for 25 wt% ammonium thiocyanate. The temperature-dependent conductivity of polymer electrolyte follows Arrhenius hopping relation. Thermogravimetric analysis has been used to ascertain the thermal stability of the polymer electrolytes. Atomic force microscopy analysis predicts the roughness parameter of the sample with higher conductivity. [ABSTRACT FROM AUTHOR]

Poly(vinylidene chloride-co-acrylonitrile)-based gel polymer electrolytes are obtained using solution casting technique. The ionic conductivity and thermal behavior of polymer electrolytes have been investigated as a function of wt% of ethylene carbonate (EC). The thermal decompositions of polymer electrolytes have been determined by thermogravimetry and differential thermal analysis in the temperature range between 30 and 800°C. All the polymer complexes can be operated upto 170°C. This range well includes the operating temperature range of the lithium polymer batteries incorporating these materials. Bulk resistance of the electrolyte from alternating current (AC) impedance analysis gives the optimal EC ratio as 80 wt% for maximum ionic conductivity. [ABSTRACT FROM AUTHOR]

In this work, polymer electrolytes composed of PAN/PMMA/LiClO4with different plasticizers are prepared using solvent casting technique. Ionic conductivity of the electrolytes is evaluated with the help of ac impedance study at various temperatures. Structural and the complexation of the prepared electrolytes are studied by XRD and FTIR analysis, respectively. Thermogravimetric/differential thermal analysis (TG/DTA) is used to find the thermal stability of the polymer electrolytes. PAN/PMMA/EC/LiClO4-based plasticized polymer electrolyte is found to possess optimal properties in terms of conductivity and thermal stability. Porous nature of the polymer gel electrolytes is also confirmed by SEM analysis. [ABSTRACT FROM PUBLISHER]

Polyvinylidene fluoride (PVdF)-polyethyl methacrylate (PEMA) based electrolytes comprising a binary mixture of solvents (EC and PC) (ethylene carbonate and propylene carbonate) and lithium salts LiX (X = ClO4, BF4, CF3SO3) have been prepared using solvent casting technique. The prepared electrolytes were subjected to ionic conductivity, XRD, SEM, and FTIR analysis to understand the salt contribution. Comparison of conductivity studies of the electrolytes with the three salts has also been made. These electrolytes exhibited good electrochemical properties, because they have an ionic conductivity of the order of 10-3 S cm-1, an electrochemical window exceeding 4.5 V and lithium ion transference number averaging above 0.75. Because, the complex containing LiClO4 exhibited maximum conductivity among the other complexes studied, DMA and CV analyses were also been performed and the results are reported. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

Polymer blend electrolytes comprising of poly(vinyl acetate), poly(vinylidene fluoride-co-hexafluoropropylene), LiClO, and EC-based plasticizer combinations (EC + PC, EC + GBL, EC + DMP, EC + DBP, EC + DEC) are prepared by solvent casting technique. Ionic conductivities of the electrolytes are determined by ac impedance studies in the temperature range 303-363 K. Among the various combinations of plasticizers, EC + PC added complex exhibits maximum ionic conductivity of the order of 10 S cm and the temperature-dependent ionic conductivity plots seem to obey the VTF relation. The structural and complex formations of the prepared samples have been confirmed by X-ray diffraction analysis. DSC technique is used to study the thermal behaviour. The surface images of the sample having maximum ionic conductivity are analyzed with the help of SEM and AFM techniques. [ABSTRACT FROM AUTHOR]

Abstract: Plasticized polymer electrolyte films containing poly (vinyl acetate) (PVAc)/poly(methyl methacrylate) (PMMA)–LiClO4 with different plasticizers are prepared by solvent casting technique. Complexation of the prepared electrolytes is confirmed by X-ray diffraction analysis and Fourier Transform Infra red analysis. Ionic conductivities of the electrolytes are determined by AC impedance studies in the temperature range of 303–343K. The temperature dependent ionic conductivity plot seems to obey Vogel–Tamman–Fulcher relation. The ionic transport in the polymer electrolytes has been discussed on the basis of free volume theory. Thermal stability and the surface morphology of the polymer electrolytes are examined by using thermogravimetric/differential thermal analysis and scanning electron microscope respectively. The highest ionic conductivity 5.064×10−4 Scm−1 have been observed for ethylene carbonate based complex because of the higher dielectric constant (89.6 at 40°C) among the other plasticizers. [ABSTRACT FROM AUTHOR]

Novel multiwalled carbon nano tubes (MWCNTs) incorporated electrolyte membrane based on a blend of poly(vinyl acetate), poly(vinylidene fluoride-hexafluoropropylene), were prepared by solution casting technique using lithium perchlorate as a metallic salt. The prepared membranes were subjected to X-ray diffraction analysis, impedance spectroscopy, and atomic force microscopic studies. The incorporation of MWCNTs greatly enhanced the ionic conductivity and is in the order of 10-3Scm-1. The temperature-dependent ionic conductivity of the electrolyte membrane seems to obey Voggel-Tamman-Fulcher relation. The rms roughness of the nano composite polymer electrolyte over the scanned area is of the order of 38 nm and the surface images of the electrolytes have been depicted using a scanning electron microscope. The change in viscosity of the polymer complexes was also identified using photoluminescence emission spectra. [ABSTRACT FROM AUTHOR]

To our knowledge, the present study is the first attempt to evaluate the effect of different process parameters on the amount of polyelectrolyte adsorbed on a cotton textile substrate via sequential adsorption of negatively charged poly (styrene sulfonate) (PSS) and positively charged poly (allylamine hydrochloride) (PAH) using layer-by-layer (LBL) self-assembly nanocoating process. A considerably different polymer adsorption behaviour was observed from thick adsorbed layers to thin adsorbed layer with different degree of layer penetration and ionic pair formation over the pH range (2.5 - 9.0) studied. The amount of polyelectrolyte adsorption on cotton fabric was evaluated by measuring the colour value (K/S) of methylene blue absorbed cotton surface. Contact angle measurement revealed that the extent of binding of the oppositely charged polyions on the fabric depends on the pH of the polyelectrolyte solution and 'zipped-up' structure with more ion pair formation was observed at the pH range 4.5 - 6.5. At higher temperature, the amount of polyelectrolyte adsorbed within the multilayers was higher. An increased deposition of PSS and PAH was observed with increase in electrolyte (NaCl) concentration. The amount of PSS and PAH adsorption increased up to 0.03 (M) of PSS and 0.01 (M) of PAH concentrations, respectively. A dipping time of 5 min was sufficient to have a maximum deposition of the polyelectrolyte multilayers. [ABSTRACT FROM AUTHOR]

Plasticized poly(vinyl chloride)/poly(ethyl methacrylate) PVC/PEMA-based blend polymer electrolyte films containing lithium perchlorate (LiClO4) as a salt were prepared by solvent casting technique. The effects of the plasticization on structural, thermal and electrical properties of the plasticized polymer blend electrolytes were investigated. The changes in the structural and complex formation properties of the materials were studied by XRD and FTIR techniques. Dielectric relaxation studies of the polymer electrolyte have been undertaken, and the results are discussed. TG/DTA technique is used to study the thermal stability. Complex impedance analysis is used to calculate the bulk resistance of the complexes. The effect of different plasticizer on the structural and physical properties of polymer blend electrolyte is well correlated. [ABSTRACT FROM AUTHOR]

Abstract: Composite electrolyte films consisting of poly(vinylchloride), poly(acrylonitrile), ethylene carbonate, LiClO4 and also TiO2 particles have been prepared by solution casting technique. The effect of inorganic filler on the conductivity of the blended polymer electrolyte was studied. A conductivity of (7.57×10−5 Scm−1) is achieved at room temperature for the composition PVC–PAN–LiClO4–EC (4.8–19.2–8–68), whereas it improves two orders of magnitude (4.46×10−3 Scm−1) upon dispersing fine particles of TiO2 as inert filler. The role of ceramic phase is to reduce the melting temperature which is ascertained from the thermogravimetric/differential thermal analysis. [Copyright &y& Elsevier]

Abstract: To investigate the effects of salt concentration, LiBF4 was incorporated into a PVdF–PVC based polymer blend and thin electrolytes were prepared by solution casting technique. The obtained thin films were subjected to various characterizations such as FTIR, XRD and TG/DTA analysis to study their complex behaviour, amorphicity and thermal stability, respectively. The ionic conductivities of the electrolytes were measured by AC impedance. A PVdF (80)–PVC (20)–LiBF4 (8wt%) polymer electrolyte was found to have high conductivity compared to other complexes. Similar investigations were also repeated with a LiClO4 salt in the above blend and the electrical conductivity was found to be higher in the polymer complex having 8wt% of salt concentration. [Copyright &y& Elsevier]

An investigation is carried out on gel polymer electrolytes consisting of poly (vinylidene fluoride) (PVdF) as a host polymer, lithium perchlorate (LiClO4), lithium triflate (LiCF3SO3) as salts and mixture of ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers. Polymer thin films were prepared by solvent casting technique and the obtained films were subjected to different characterizations, to confirm their structure, complexation and thermal changes. X-ray diffraction revealed that the salts and plasticizers disrupted the crystalline nature of PVdF based polymer electrolytes and converted them into an amorphous phase. TG/DTA studies showed the thermal stability of the polymer electrolytes. The role of interaction between polymer hosts on conductivity is discussed using the results of a.c. impedance studies. Room temperature (28°C) conductivity of 2.786 x 10-3 Scm-1 was observed in PVdF (24)-EC/PC (68)-LiCF3SO3 (2)/LiClO4 (6) polymer system. [ABSTRACT FROM AUTHOR]

Abstract: Hybrid, solid polymer electrolyte films consisting of poly(vinyl chloride) (PVC), poly(vinylidine fluoride) (PVdF), LiN(CF3SO2)2 and ethylene carbonate (EC) are prepared using solvent casting technique. The formation of polymer–salt complex has been confirmed by FTIR spectral studies. The effect of the PVC/PVdF blend ratio on ionic conductivity is explained in terms of the morphology of the film. The highest ionic conductivity value (5.766×10− 3 S cm− 1) is obtained for PVC–PVdF–LiN(CF3SO2)2–EC (Film F3) at room temperature. The electrochemical stability window of Film F3 was about 4.5 V determined from the linear sweep voltammetry plot. The surface morphology of the above membrane was also observed by scanning electron microscope (SEM). Polymer electrolyte film bereft of PVC appears very promising for Li battery applications. [Copyright &y& Elsevier]

In order to optimize the blend composition of PVA–PVdF–LiClO4 polymer electrolytes, flexible films are prepared using solvent casting technique. The complex formation has been ascertained by XRD and FTIR analyses. The AC conductivity studies are carried out to evaluate the ambient temperature conductivity of the polymer electrolytes. The maximum conductivity value 3.0364×10−5 S/cm has been observed for PVA (67.5)–PVdF (22.5)–LiClO4 (10 wt%) system. Thermal stability of the film exhibiting maximum conductivity is studied and the results are discussed. [Copyright &y& Elsevier]

Solid polymer electrolytes of high ionic conductivity are prepared using poly(vinyl alcohol) (PVA) complexed with various lithium salts such as LiClO4, LiCF3SO3 and LiBF4, and dimethyl phthalate (DMP) as plasticizer. The solid polymer electrolyte (SPE) films are characterized by X-ray diffraction, FTIR spectroscopy and ac impedance spectroscopic studies. Conductivity studies of these SPE films are carried out in the temperature range 302–373 K. The temperature dependence of the conductivity of polymer electrolyte films seems to obey VTF relation. [Copyright &y& Elsevier]

Polymer electrolytes comprising a blend of poly(vinyl alcohol) (PVA) and poly(methyl methacrylate) (PMMA) with different concentrations of LiBF4 are prepared using a solvent-casting technique. The structure and complexation of the electrolytes are studied by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The ionic conductivities of the electrolytes are measured in the temperature range 302–373 K. The maximum conductivity (1.2886×10−3 S cm−1) is obtained for a polymer complex with 8 wt.% LiBF4. The thermal stability of this electrolyte is examined by thermogravimetric/differential thermal analysis (TG/DTA). [Copyright &y& Elsevier]

Polymer electrolyte membranes comprising poly(vinylidene fluoride) (PVdF), poly(methylmethacrylate) (PMMA), LiClO4 and DMP were prepared. Structural characterization was carried out on the polymer electrolyte thin film using XRD. The complex formation of polymer and salt has been confirmed by XRD and FT-IR spectral studies. The ac conductivity studies were performed to evaluate the ambient temperature conductivity of the polymer electrolyte membranes. The influence of blend compositions on the ionic conductivity was discussed. The maximum conductivity for PMMA (7.5)–PVdF (17.5)–LiClO4 (8)–DMP (67) system is found to be 4.2×10−3 S cm−1 at 303 K. [Copyright &y& Elsevier]

New gel polymer electrolytes containing poly(vinylidene chloride-co-acrylonitrile) and poly(methyl methacrylate) are prepared by solution casting method. With the addition of 60 wt.% of EC to PVdC-AN/PMMA blend, ionic conductivity value 0.398×10-6 S cm−1 has been achieved. XRD and FT-IR studies have been conducted to investigate the structure and complexation in the polymer gel electrolytes. The FT-IR spectra show that the functional groups C=O and C≡N play major role in ion conduction. Thermal stability of the prepared membranes is found to be about 180°C. [ABSTRACT FROM AUTHOR]

Abstract: Plasticised polymer blend electrolytes based on poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP) and poly(ethyl methacrylate) (PEMA) were prepared for different lithium salts LiX (X=ClO4, CF3SO3, BF4 and N[CF3SO2]2) using facile solution casting. To confirm the structures and complexations of the electrolyte films, the prepared electrolytes were subjected to XRD and FTIR analysis. TG–DTA was used to ascertain the thermal stability of the electrolytes, and the porous nature of the electrolytes was identified using scanning electron microscopy via ion-hopping conduction. AC impedance analysis was performed for all the electrolyte samples at various temperatures from 303 to 363K. The results suggest that among the various lithium salts, LiN[CF3SO2]2-based electrolytes exhibited the highest ionic conductivity (0.918×10−3 Scm−1). The temperature dependence of the ionic conductivity also complies with the VTF relation. [Copyright &y& Elsevier]

Abstract: Composite polymer electrolytes (CPE) composed of Poly (vinyl acetate) (PVAc), poly (vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP), barium titanate (BaTiO3) nanofiller, lithium tetrafluroborate (LiBF4), ethylene carbonate (EC) and propylene carbonate (PC) were prepared using simple solution casting method. The BaTiO3 nanofillers were homogeneously dispersed in the polymer electrolyte matrix and exhibited excellent interconnection with PVAc/PVdF-co-HFP/EC/PC/LiBF4 polymer electrolyte. The addition of BaTiO3 nanofillers improved the ionic conductivity of the polymer electrolytes to some extent when the content of the BaTiO3 is 8wt.%. The addition of BaTiO3 also enhanced the thermal stability of the electrolyte. The structural and complex formations of the composite electrolyte membranes were confirmed by X-ray diffraction and FTIR analysis, respectively. Surface morphology of the samples was depicted using scanning electron microscope and atomic force microscope studies. [Copyright &y& Elsevier]

Abstract: The present work describes the Li-ion conduction in Poly(vinyl acetate) (PVAc) based polymer blend electrolytes have been synthesized by solvent casting technique for lithium battery applications. Characterization by XRD, SEM, AFM, FTIR, TG/DTA and photoluminescence was performed for synthesized polymer electrolytes. The thermal behaviour of the samples was ascertained from differential scanning calorimeter (DSC) and TG/DTA. The temperature dependence of conductivity of the polymer electrolytes was measured and the maximum ionic conductivity of 0.5269×10−4 Scm−1 at 303K for PVAc:PVdF-co-HFP ((25/75)wt%):LiClO4 (8wt%) complex. Surface morphology was examined from various surface scanning techniques such as scanning electron microscope (SEM) and atomic force microscope (AFM). Photoluminescence measurements demonstrated that the PVAc based polymer blend electrolyte shows minimum intensity and the results are detailed in this paper. [Copyright &y& Elsevier]

The present study relates to form a self-assembled coating on cotton fabric using layer-by-layer (L-B-L) technique to impart antimicrobial property. Poly(styrenesulfonate) (PSS) and synthesised silver loaded chitosan (CS-Ag) nanoparticles were used as anionic and cationic agents, respectively, for the L-B-L electrostatic assembly of polyelectrolytes. The alternate L-B-L deposition of PSS and CS-Ag nanoparticles on fabric was done up to 15 bi-layers, which was confirmed by measuring the change in depth of colour of fabric after each single layer deposition. Scanning electron micrographs showed the successful deposition of CS-Ag nanoparticles as the topmost surface layer of coated fabric, which was further reaffirmed by X-ray photoelectron spectroscopy analysis. Results of both qualitative and quantitative analysis showed enhancement in the antibacterial activity of fabric coated L-B-L with CS-Ag nanoparticles (using minimal loading of silver) with respect to that of fabric coated L-B-L with chitosan (CS) nanoparticles. This was further substantiated by sustained release of Ag+ from fabric coated L-B-L with CS-Ag nanoparticles, as observed by atomic absorption spectroscopy. Besides, no adverse effect on the physical and mechanical properties of the fabric, such as air-permeability, tensile strength and bending (flexural) rigidity, was observed after L-B-L coating of nanoparticles. Unlabelled Image • Synthesis of silver loaded chitosan (CS-Ag) nanoparticles • Layer-by-layer (L-B-L) coating of synthesised CS-Ag nanoparticles on cotton fabric • 100% antibacterial activity of CS-Ag nanoparticle coated fabric against both Gram-positive and Gram-negative bacteria • Sustained release of Ag+ from CS-Ag nanoparticle coated fabric • No adverse effect of L-B-L coating on physical properties of fabric [ABSTRACT FROM AUTHOR]