International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Special Issue: 09 | Sep -2017
p-ISSN: 2395-0072
www.irjet.net
One Day International Seminar on Materials Science & Technology (ISMST 2017) 4th August 2017 Organized by
Department of Physics, Mother Teresa Women’s University, Kodaikanal, Tamilnadu, India
DIELECTRIC DISPERSION AND RELAXATION BEHAVIOUR OF SYNTHESIZED POLYMER ELECTROLYTE MEMBRANE FOR ELECTROCHEMICAL APPLICATIONS S. PORCHELVIa,b , R. KANNANb, S. RAJASHABALAc , P. BAHAVAN PALANId, K.SAINUL ABIDINb Dept. of Physics, Sri Subramanya College of Engg. and Tech., Palani-624615 Dept. of Physics, University College of Engg., Anna University, Dindigul-624622 c School of Physics, Madurai Kamaraj University, Madurai- 625021. dDept. of Physics, National Institute of Technology, Trichy- 620 015. brksrsrk@gmail.com, a,b porchelvi33@gmail.com --------------------------------------------------------------------***----------------------------------------------------------------------a
b
Abstract - Sulfonated poly ether ether ketone (SPEEK) based polymer electrolyte membrane has been prepared by solution casting technique. The dielectric and proton conductivity of the blend membrane have been investigated by means of impedance spectroscopy which shows the existence of bulk and material-electrode interface properties of the membranes. The dielectric constant (ε’ & ε”) decreases with increase of frequency in the low frequency region due to the presence of space charge polarization whereas frequency independent behavior is observed in the high frequency region due to the dynamics of cations coordinated polymer chain segments. Moreover the electrical modulus formalism (M’ & M”) predicts a non Debye type relaxation. The scaling behavior of the membrane shows that the dynamical relaxation process is temperature as well as composition independent. The obtained results demonstrate that the developed composite membrane could be utilized for electrochemical applications.
1. INTRODUCTION The growing awareness on environmental issues and energy crisis due to depletion of fossil fuels pressing researchers in finding alternative source of energy with almost zero emissions. The development of polymer electrolyte membrane (PEM) with higher ionic conductivity is the main objective in recent research. PEM have been studied for their application in batteries, fuel cells and sensors. Fuel cells are excellent electrochemical energy conversion devices that directly convert the chemical energy of the fuel into electric energy with almost zero emission of unwanted gas [1]. PEEK is a highly thermoplastic polymer with excellent mechanical, chemical and thermal properties. Sulfonation of PEEK introduces hydrophilic properties to polymer. Polyethersulfone (PES) has high glass transition temperature, good mechanical, thermal and chemical stability. Blending of one polymer with another is an effective way of achieving good qualities of both the polymers [2]. It becomes important to understand the ion transport mechanism along with polymer segmental relaxation processes in polymer electrolytes. The main objective of this current work is to investigate the conductivity and dielectric properties of the prepared polymer electrolyte membrane. In this approach, both frequency and temperature are varied for dielectric spectroscopy, so that a wide range of molecular mobility can be examined.
2. Materials and Methods Poly (oxy – 1, 4 – Phenyleneoxy – 1, 4 – Phenylene carbonyl – 1, 4 Phenylene) (PEEK; MW= 20800) (Sigma Aldrich, USA) Poly (oxy-1, 4- phenylene sulfonyl- 1, 4 – phenylene) (PES; MW=35000) (Sigma Aldrich, USA). N, N – Dimethyl sulfoxide (DMSO), Sulfuric acid (H2SO4) (98%) (Merck, Germany). The polymer electrolyte membranes were prepared by solution casting technique. PEEK was sulfonated using sulfuric acid and the sulfonation of PEEK was carried out as reported earlier [3]. Appropriate weight ratio of SPEEK and PES polymer were dissolved separately in DMSO and the solutions were mixed together and casted in Petri dish then dried to form a blend membrane. Impedance analysis of the samples was carried out using frequency response analyzer from the impedance data Dielectric, Modulus and scaling parameters of the samples are studied.
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