Conductivity Studies of Plasticized-poly(methylmethacrylate) (PMMA) Polymer Electrolytes Films

Abstract

In the present study, five systems of samples have been prepared by the solution casting technique. Polymethylmethacrylate (PMMA) is used as a based polymer. Ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers. The salt that was selected for this study is lithium triflate (LiCF3SO3). The pure PMMA sample is taken as a reference. The five systems are the (PMMA–EC) system, the (PMMA–PC) system, the (PMMA‐LiCF3SO3) system, the ([PMMA‐EC]‐LiCF3SO3) system and the ([PMMA–PC]‐LiCF3SO3) system. The conductivity for each system is characterized using impedance spectroscopy. The conductivity of the pure PMMA, the (PMMA–EC) system and the (PMMA–PC) system at room temperature is 2.37×10−9 Scm−1, 3.63×10−8 Scm−1 and 4.18×10−8 Scm−1 respectively. On addition of salt in the (PMMA–LiCF3SO3) system, the conductivity is increased by two orders of magnitude. The conductivity for the ([PMMA–EC]‐LiCF3SO3) system and the ([PMMA–PC]‐LiCF3SO3) system is 3.54×10−5 Scm−1 and 2.06×10−5 Scm−1 respectively. The conductivity temperature–dependence studies are then performed on the highest conducting film from the (PMMA–LiCF3SO3) system, the ([PMMA—EC]‐LiCF3SO3) system and the (PMMA–PC]‐LiCF3SO3) system. The conductivity temperature studies are conducted in the temperature range between 303 K and 373 K. The result shows that the conductivity is increased as the temperature increased. The increase of conductivity is due to the increase in number of mobile ions. It shows that the conductivity for all of these systems obeys Arrhenius rule where it indicates that the points lie in an almost straight line. The activation energy, Ea for the (PMMA–35wt % LiCF3SO3) system, the ([PMMA–EC]‐35wt % LiCF3SO3) system and the ([PMMA–PC]–35wt % LiCF3SO3) system is 0.21 eV, 0.10 eV and 0.15 eV respectively.