Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
DIAS, Bruna L. et al. Electrochemical and electrochromic properties of poly(4,4" dimethoxy 3'-methyl 2,2':5',2" terthiophene). J. Braz. Chem. Soc. [online]. 2005, vol.16, n.4, pp. 733-738. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532005000500009.
This work describes the electrochemical, spectroelectrochemical and electrochromic properties of poly(4,4" dimethoxy 3'-methyl 2,2':5',2" terthiophene) thin films. The effect of temperature on the electropolymerization was studied by cyclic voltammetry measured in situ. The temperatures used were -10, 0, 10, 20, and 40 ºC. Results indicate that the electropolymerization temperature directly affect the degree of chain organization. The optical response time for bleaching was 0.8 s and for coloring 0.3 s (for films synthesized at 40 ºC, 60 nm thick). After 1400 electrochromic cycles, the chromatic contrast at 570 nm changes from 31 to 14%. The coloration efficiency was enhanced as a function of redox cycling. This was probably caused by a decrease in the injected charge necessary for the color change, suggesting that the electroactive losses occurring during the cycles are related to sites not responsible for electrochromic contrast.
Keywords : thiophene derivatives; electrochromic properties; electro polymerization; electrochromism; conducting polymer.