Role of Dielectric Constant on Ion Transport: Reformulated Arrhenius Equation

Shujahadeen B Aziz

doi:10.1155/2016/2527013

Abstract

Solid and nanocomposite polymer electrolytes based on chitosan have been prepared by solution cast technique. The XRD results reveal the occurrence of complexation between chitosan (CS) and the LiTf salt. The deconvolution of the diffractogram of nanocomposite solid polymer electrolytes demonstrates the increase of amorphous domain with increasing alumina content up to 4 wt.%. Further incorporation of alumina nanoparticles (6 to 10 wt.% Al2O3) results in crystallinity increase (large crystallite size). The morphological (SEM and EDX) analysis well supported the XRD results. Similar trends of DC conductivity and dielectric constant with Al2O3concentration were explained. The TEM images were used to explain the phenomena of space charge and blocking effects. The reformulated Arrhenius equation (σ(ε′,T)=σoexp(-Ea/KBε′T)) was proposed from the smooth exponential behavior of DC conductivity versus dielectric constant at different temperatures. The more linear behavior of DC conductivity versus1000/(ɛ′×T)reveals the crucial role of dielectric constant in Arrhenius equation. The drawbacks of Arrhenius equation can be understood from the less linear behavior of DC conductivity versus1000/T. The relaxation processes have been interpreted in terms of Argand plots.

Highlights

Chitin, poly(β-(1→4)-N-acetyl-D-glucosamine), is a natural polysaccharide of major importance, first identified in 1884
It is obvious that the peak of pure chitosan at 15.5∘ shifted to 12.6∘ in CS : lithium triflate (LiTf) systems
In this research work solid and nanocomposite polymer electrolytes based on chitosan have been prepared by the well-known solution cast technique

Summary

Introduction

Poly(β-(1→4)-N-acetyl-D-glucosamine), is a natural polysaccharide of major importance, first identified in 1884. This biopolymer is synthesized by an enormous number of living organisms; and considering the amount of chitin produced annually in the world, it is the most abundant polymer after cellulose [1]. Chitosan has great potential as a biomaterial because of [3] good biocompatibility, biodegradability, low toxicity, low cost [4], antimicrobial activity [5], hydrophilicity which certainly be of benefit to the fuel cell operation, and chemical and thermal stability at higher temperatures [6]. Chitosan has become of great interest as an underutilized resource and as a new functional biomaterial of high potential in various fields [7]. The unique properties which separate chitosan from other biopolymers are the presence of amino groups [8] as depicted in Scheme 1(b)

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Conclusion