Ionic conduction mechanism of potato starch–based biopolymer electrolytes complexed with potassium hydroxide

2018 ◽  
Author(s):  
S. Z. Z. Abidin ◽  
M. S. Sak Ari ◽  
S. Navaratnam ◽  
N. K. Jaafar ◽  
M. Z. A. Yahya
2015 ◽  
Vol 1108 ◽  
pp. 27-32 ◽  
Author(s):  
A.S. Samsudin ◽  
M.I.N. Isa

This study deals with the ionic conduction mechanism of carboxymethyl cellulose (CMC) – NH4Br biopolymer electrolytes (BPEs) plasticized with ethylene carbonate (EC) prepared via solution-casting technique. The ionic conductivity of BPEs system was characterized by using impedance spectroscopy and shows the highest conductivity at ambient temperature for CMC–NH4Br BPEs is 1.12 x 10-4 S/cm and enhanced to 3.31 x 10-3 S/cm with the addition of 8 wt. % EC. The conductivity–temperature plot of the BPEs system obeys Arrhenius law where R2~1. The dielectric values were found to increase with increasing temperature thus divulged that the BPEs system to be non-Debye type. The temperature dependence of the power law exponent shows the CMC–NH4Br–EC BPEs system follows the quantum mechanical tunneling (QMT) model of conduction mechanism, where the enhanced protonation of NH4Br with addition of EC makes the charge transfer (polarons) able to tunnel through the potential barrier that exists between the lone pair electrons in carboxyl group of CMC and NH4Br.


2021 ◽  
Vol 18 (38) ◽  
pp. 137-148
Author(s):  
Alvaro ARRIETA

Background: Solid biopolymer electrolytes are a type of material with high technological potential used in the development of solar cells, batteries, fuel cells, among others, due to their biodegradable nature and low environmental impact. Aim: This study aimed to evaluate the effect of the botanical origin of the starch used to prepare solid biopolymeric electrolyte films on its electrochemical and thermal properties and to establish the variations in thermal decomposition temperatures and redox potentials depending on the botanical origin of the starch used. Methods: Films of solid biopolymer electrolyte were made by thermochemical synthesis processes using corn starch, cassava starch, potato starch, glycerol, polyethylene glycol, and glutaraldehyde as plasticizers and lithium perchlorate salt. The synthesis solutions were taken to an oven at 70 °C for 48 hours. The films were characterized electrochemically by cyclic voltammetry using a dry electrochemical cell and thermally by differential scanning calorimetry and thermogravimetric analysis. Results and Discussion: The results showed that the electrochemical behavior of the films was similar in terms of registered redox processes. However, the potential values of the oxidation and reduction were different, as are the stability and intensity of the processes. On the other hand, the thermal analysis allowed establishing two decomposition processes in each of the films studied; the first process was due to dehydration and depolymerization phenomena in the films. The temperatures recorded were 59.0 °C, 58.9 °C, and 89.9 °C for potato starch, cassava starch, and corn starch films. The second process evidenced the thermal decomposition at different temperatures, 267.7 °C in potato starch films, 280.6 °C in corn starch films, and 287.1 °C in cassava starch films. Conclusions: It could be concluded that the botanical origin of the starch used in the synthesis of solid biopolymer electrolyte films affects its behavior and electrochemical and thermal stability.


1952 ◽  
Vol 30 (8) ◽  
pp. 603-607 ◽  
Author(s):  
J. Ross Colvin ◽  
W. H. Cook ◽  
G. A. Adams

The usefulness of electrophoretic patterns of polysaccharides in molar alkali as a general criterion of the purity of these substances has been studied. No clear separation of the components of a hemicellulose, of wheat starch, or of potato starch could be demonstrated. Similarly, mixtures of wheat starch and inulin, pectin and sodium alginate, laminarin and sodium alginate, inulin and wheat starch plus sodium alginate could not be resolved in 1 M potassium hydroxide. Nonetheless, mixtures of laminarin and sodium alginate separated rapidly at pH 6.8 and 10.4. Contrary to previous reports, it is shown that the electrophoretic technique cannot be used with confidence as a general criterion of the purity of polysaccharides in molar alkali. However, it may be applicable for the characterization and fractionation of a limited class of polysaccharides which are soluble close to neutrality.


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