Optical and electrochemical properties of regiosymmetric and soluble alkylenedioxyselenophene-based electrochromic polymers, namely poly (3,3-dibutyl-3,4-, are highlighted. It is noted that these unique polymers have low bandgaps (1.57-1.65 eV), and they are exceptionally stable under ambient atmospheric conditions. Polymer films retained 82-97% of their electroactivity after 5000 cycles. The percent transmittance of PProDOS-C n (n ¼ 4, 6, 10) films found to be between 55 and 59%. Furthermore, these novel soluble PPro-DOS-C n polymers showed electrochromic behavior: a color change form pure blue to highly transparent state in a low switching time (1.0 s) during oxidation with high coloration efficiencies (328-864 cm 2 C À1 ) when compared to their thiophene analogues. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: [4398][4399][4400][4401][4402][4403][4404][4405] 2011

The optical and electrochemical properties of a regioregular and soluble alkylenedioxyselenophenebased electrochromic polymer, namely poly (3,3-didecyl-3,4-dihydro-2H-selenopheno[3,4-b][1,4] dioxepine (PProDOS-C 10 ), which is synthesized by electrochemical polymerization, are highlighted. It is noted that this unique polymer has a low band gap (1.58 eV) and is exceptionally stable under ambient atmospheric conditions. Polymer films retain 97% of their electroactivity after 40 000 cycles. The percentage transmittance of a PProDOS-C 10 film was found to be 56.4% at 638 nm and 55.8% at 700 nm. Furthermore, this novel soluble PProDOS-C 10 polymer shows an electrochromic behavior: a color change from pure blue to a highly transparent state in a low switching time (1.0 s) during oxidation, with high coloration efficiencies (328 cm 2 C À1 at 638 nm and 319 cm 2 C À1 at 700 nm) when compared to its thiophene analogue.