M. F. Z. Kadir

FTIR Studies of plasticized poly(vinyl alcohol)-chitosan blend doped With NH4NO3 polymer electrolyte membrane

Fourier transform infrared (FTIR) spectroscopy studies of poly(vinyl alcohol) (PVA), and chitosan polymer blend doped with ammonium nitrate (NH(4)NO(3)) salt and plasticized with ethylene carbonate (EC) have been performed with emphasis on the shift of the carboxamide, amine and hydroxyl bands. 1% acetic acid solution was used as the solvent. It is observed from the chitosan film spectrum that evidence of polymer-solvent interaction can be observed from the shifting of the carboxamide band at 1660 cm(-1) and the amine band at 1591 cm(-1) to 1650 and 1557 cm(-1) respectively and the shift of the hydroxyl band from 3377 to 3354 cm(-1). The hydroxyl band in the spectrum of PVA powder is observed at 3354 cm(-1) and is observed at 3343 cm(-1) in the spectrum of the PVA film. On addition of NH(4)NO(3) up to 30 wt.%, the carboxamide, amine and hydroxyl bands shifted from 1650, 1557 and 3354 cm(-1) to 1642, 1541 and 3348 cm(-1) indicating that the chitosan has complexed with the salt. In the PVA-NH(4)NO(3) spectrum, the hydroxyl band has shifted from 3343 to 3272 cm(-1) on addition of salt from 10 to 30 wt.%. EC acts as a plasticizing agent since there is no shift in the bands as observed in the spectrum of PVA-chitosan-EC films. The mechanism of ion migration is proposed for the plasticized and unplasticized PVA-chitosan-NH(4)NO(3) systems. In the spectrum of PVA-chitosan-NH(4)NO(3)-EC complex, the doublet CO stretching in EC is observed in the vicinity 1800 and 1700. This indicates that there is some interaction between the salt and EC.

Conductivity and electrical properties of corn starch–chitosan blend biopolymer electrolyte incorporated with ammonium iodide

This work focuses on the characteristics of polymer blend electrolytes based on corn starch and chitosan doped with ammonium iodide (NH4I). The electrolytes were prepared using the solution cast method. A polymer blend comprising 80wt% starch and 20wt% chitosan was found to be the most amorphous blend and suitable to serve as the polymer host. Fourier transform infrared spectroscopy analysis proved the interaction between starch, chitosan and NH4I. The highest room temperature conductivity of (3.04±0.32)◊10 4 Scm 1 was obtained when the polymer host was doped with 40wt% NH4I. This result was further proven by field emission scanning electron microscopy study. All electrolytes were found to obey the Arrhenius rule. Dielectric studies confirm that the electrolytes obeyed non-Debye behavior. The temperature dependence of the power law exponent s for the highest conducting sample follows the quantum mechanical tunneling model.

Innovative method to avoid the reduction of silver ions to silver nanoparticles

In this research work an innovative method is used to prevent the silver ion reduction in solid polymer electrolytes. The x-ray diffraction (XRD) results reveal the disruption of the crystalline nature of chitosan (CS) and formation of silver nanoparticles upon addition of silver triflate (AgTf) salt. The UV-vis measurement confirms the existence of silver nanoparticles via the broad surface plasmon resonance (SPR) peak. Upon the addition of Al2O3 nanoparticles the SPR peak intensity is greatly reduced. The amorphous domain of the CS:silver triflate (CS:AgTf) system increases with the addition of Al2O3 nanoparticles up to 4 wt.%. Deconvolution of the XRD results reveals that a larger crystallite size is obtained for higher Al2O3 concentrations and the peaks due to silver nanoparticles almost disappear. Scanning electron microscope (SEM) analyses show that Al2O3 nanoparticles are well dispersed at low concentrations and the leakage of chains of silver nanoparticles to the membrane surface almost disappear. The XRD, UV-vis, SEM and energy-dispersive x-ray (EDX) results strongly support that the reduction of silver ions to silver nanoparticles (Ag + →Ag°) in the CS:silver triflate system is significantly avoided upon the addition of an Al2O3 filler.

\left( {\rm A}{{{\rm g}}^{+}}\to {\rm Ag}{}^\circ \right)

This paper focuses on the conductivity and transport properties of chitosan-based solid biopolymer electrolytes containing ammonium thiocyanate (NH4SCN). The sample containing 40 wt% NH4SCN exhibited the highest conductivity value of (1.81 ± 0.50) × 10−4 S cm−1 at room temperature. Conductivity has increased to (1.51 ± 0.12) × 10−3 S cm−1 with the addition of 25 wt% glycerol. The temperature dependence of conductivity for both salted and plasticized systems obeyed the Arrhenius rule. The activation energy (Ea) was calculated for both systems and it is found that the sample with 40 wt% NH4SCN in the salted system obtained an Ea value of 0.148 eV and that for the sample containing 25 wt% glycerol in the plasticized system is 0.139 eV. From the Fourier transform infrared studies, carboxamide and amine bands shifted to lower wavenumbers, indicating that chitosan has interacted with NH4SCN salt. Changes in the C–O stretching vibration band intensity are observed at 1067 cm−1 with the addition of glycerol. The Rice and Roth model was used to explain the transport properties of the salted and plasticized systems.

in silver ion conducting based polymer electrolytes

Abstract The highest conducting sample 11 wt-% poly(vinyl alcohol)+7 wt-% chitosan–12 wt-% ammonium nitrate (NH4NO3)–70 wt-% ethylene carbonate in the poly(vinyl alcohol)–chitosan–NH4NO3–ethylene carbonate solid polymer electrolyte system has been used in the fabrication of an electrical double layer capacitor (EDLC). The solid polymer electrolyte has been prepared by the solution casting method, and the Dr Blade method is used in the preparation of the electrodes. The conductivity of the film is 1·60×10−3 S cm−1 at room temperature. From linear sweep voltammetry, the decomposition voltage of the electrolyte material is ∼1·70 V. The EDLC has been cycled 100 times at 0·095 and 0·381 mA cm−2 current densities. The capacitance of the EDLC is 27·1 and 16·7 F g−1 for the current density applied at 0·095 and 0·381 mA cm−2 charge–discharge currents respectively.

Conductivity and transport studies of plasticized chitosan-based proton conducting biopolymer electrolytes

This work focuses on polymer electrolytes composed of a starch-chitosan blend host, ammonium iodide (NH4I) and glycerol. Fourier transform infrared (FTIR) analysis confirms the interaction of starch-chitosan-NH4I-glycerol. The highest room temperature conductivity is (1.28 ± 0.07) × 10−3 S cm−1, obtained by a sample containing 30 wt% glycerol. Dielectric studies showed that the electrolytes obeyed non-Debye behavior. The total ionic transference number for the 30 wt% glycerol sample was 0.991, and the conduction mechanism for this sample followed the quantum mechanical tunneling (QMT) model. Linear sweep voltammetry (LSV) showed that this sample was electrochemically stable up to 1.90 V. The highest conducting sample was used in the fabrication of an electrical double layer capacitor (EDLC) cell.

Application of PVA–chitosan blend polymer electrolyte membrane in electrical double layer capacitor

Series of polymer blend consisting of polyethylene oxide (PEO) and graphene oxide (GO) as co-host polymer were prepared using solution cast method. The most amorphous PEO-GO blend was obtained using 90 wt.% of PEO and 10 wt.% of GO as recorded by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis proved the interaction between PEO, GO, lithium trifluoromethanesulfonate (LiCF3SO3), and ethylene sulfite (ES). Incorporation of 25 wt.% LiCF3SO3 into the PEO-GO blend increases the conductivity to  S cm−1. The conductivity starts to decrease when more than 25 wt.% salt is doped into the polymer blend. The addition of 1 wt.% ES into the polymer electrolyte has increased the conductivity to  S cm−1. Dielectric studies show that all the electrolytes obey non-Debye behavior.

The Effect of Plasticization on Conductivity and Other Properties of Starch/Chitosan Blend Biopolymer Electrolyte Incorporated with Ammonium Iodide

Two polymer electrolyte systems (unplasticized and plasticized) based on starch-chitosan blend doped with ammonium bromide (NH4Br) were prepared. The conductivity was found to be influenced by the number density (n) and mobility (μ) of the ions. The highest conducting plasticized electrolyte had n and μ values of 8.75 × 1018 cm−3 and 1.03 × 10−3 cm2 V−1 s−1, respectively. Ionic transference number for the highest conducting plasticized electrolyte was found to be 0.92. An electrochemical double layer capacitor (EDLC) using the highest conducting plasticized electrolyte was cycled for 500 times at 0.048 mA cm−2.

Conductivity and Dielectric Studies of Lithium Trifluoromethanesulfonate Doped Polyethylene Oxide-Graphene Oxide Blend Based Electrolytes

A polymer electrolyte system based on chitosan complexed with ammonium bromide (NH4Br) salt was prepared by the solution cast technique. 30 wt% NH4Br added electrolyte gave a room temperature conductivity of (4.38 ± 1.26) × 10−7 S cm−1 and increased to (2.15 ± 0.47) × 10−4 S cm−1 with addition of 40 wt% glycerol. The dependence of the conductivity on temperature proves that both chitosan–NH4Br and chitosan–NH4Br–glycerol systems are Arrhenian. The activation energy (Ea) value for 70 wt% chitosan–30 wt% NH4Br film is 0.31 eV and the Ea value for 42 wt% chitosan–18 wt% NH4Br–40 wt% glycerol film is 0.20 eV. The carboxamide band at 1640 cm−1 and the amine band at 1549 cm−1 in the spectrum of pure chitosan film shifted to 1617 and 1516 cm−1, respectively, in the spectrum of 70 wt% chitosan–30 wt% NH4Br film, indicating the occurrence of complexation between polymer and salt. The band at 1024 cm−1 in the pure chitosan film spectrum, which corresponds to the C–O stretching vibration, shifted to lower wavenumbers on addition of salt. A new band appears at 997 cm−1 on addition of 40 wt% glycerol.

Protonic Transport Analysis of Starch-Chitosan Blend Based Electrolytes and Application in Electrochemical Device

Abstract The polymer electrolyte membrane in this work was prepared using the solution casting technique. The polymer host is a blend of chitosan and polyethylene oxide. The solution of the blend was added with ammonium nitrate (NH4NO3) to supply the charge carriers for ionic conduction. From X-ray diffraction and scanning electron microscopy image, it can be inferred that the film of the 3∶2 chitosan–polyethylene oxide blend is the most amorphous and suitable to serve as polymer host. The sample containing 40 wt-%NH4NO3 exhibited the highest room temperature conductivity of 1·02×10−4 S cm−1. The salted samples were also characterised using X-ray diffraction and scanning electron microscopy in order to establish conductivity variation with different salt contents.