POLY[3-(ALKYL)THIOPHENE] DERIVATIVES AS PROMISING MATERIALS FOR ASSEMBLING AN ELECTROCHROMIC DEVICE

Abstract

3-[ω-(p-methoxyphenoxy)alkyl] thiophenes were synthesized and electrochemically polymerized on ITO/glass electrodes by the potentiostatic method. Short alkyl chains substituted thiophene derivatives are generally difficult to polymerize by electrochemical methods, however, potentiostatic deposition provided homogeneous, stable films. Spectroelectrochemical characterization of the films obtained showed that their color depends on the alkyl chain length attached to the thiophene ring. Among the investigated films, poly{3-[12-(p-methoxyphenoxy)dodecyl]thiophene} presented the best electrochromic properties and was chosen to assemble a solid state electrochromic device using poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) film deposited by spraying on ITO/PET electrodes as complementary electrode and polymer electrolyte. The device presented color variation during ca. 500 charge/discharge cycles and can be assembled under atmospheric conditions. The results obtained show promissing perspectives for its application in electrochromic displays.