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.

Filmes compósitos obtidos pela polimerização eletroquímica de ditienopirrol sobre eletrodos de platina ou ITO recobertos com um filme de poli(cloreto de vinila) foram estudados neste trabalho. Os resultados obtidos da análise térmica e de microscopia indicam a natureza compósita do material. As propriedades eletrocrômicas foram estudadas por espectroeletroquímica dinâmica e são semelhantes às propriedades do poli(ditienopirrol) puro.

Composite films obtained by the electrochemical polymerization of dithienopyrrole onto poly(vinylchloride) coated platinum or ITO electrodes were prepared and studied in this work. Results obtained by thermal analysis and microscopy show the composite nature of the material. The electrochromic properties were studied by dynamic spectroelectrochemistry and resemble those of the pure poly(dithienopyrrole) polymer.