The Changing with Dielectric Constant of the Capacitance of Single Carbon Fiber Coated with PolyThiophene and their Derivatives

Abstract

In this study, the effect of dielectric constant on the electrical, capacitive and morphological properties of single carbon fiber(SCF) electrodes coated with Poly(thiophene), Poly(3-methylthiophene), Poly(3-dodecylthiophene) or Poly(3-imidazolethiophene) was investigated. Monomers were electropolymerized separately on SCF in 5 ml solutions with different dielectric constant(ε) by Cyclic Voltammetry technique. Capacitive and morphological characteristics were determined by using suitable techniques. It was found that the oxidation potential and maximum current values of the monomers and the specific and double layer capacitance(C_sp and C_dl) values of the electrode coated with their polymers decreased with the weight increase in the –R group in the 37,5 media. C_sp values were in the same range for derivative polymer coatings, which the range of 0-3,333 Fcm^-2. When the potential was applied to the electrode, C_sp value was decreased as -R weight was increased. It was seen that the value was increased for ring group in the same conditions. In ε:37,5 C_sp value was increased to 36,666 Fcm^-2 from 21,666 Fcm^-2 when potential was increased to 0,6 V from -0,2V for Poly(3-imidazolethiophene). It was thought that solution mixtures could be more effective to change and control the electrical and capacitive properties of the electrode covered with conductive polymer.