A series of dithienothiophene-based electrochromic polymers are synthesized by a Stille coupling reaction of 2,6-bis(trimethylstannyl)dithieno[3,2-b:2',3'-d]thiophene, 2,5-dibromo-3,4-bis(dodecyloxy)thiophene, and tris(4-bromophenylamine). The resulting polymers have high molecular weights in the range of 59 200 to 81 300 g mol-1 , and good solubility in common organic solvents. The polymer films are purple/red in neutral states and gradually become gray when oxidized to an intermediate state and blue when fully oxidized. Incorporation of triphenylamine into the polymer chains has resulted in a significant increase in the redox stability, which renders this a potential method to create high-performance electrochromic polymers.
Keywords: electrochromism; heterocycles; polymers; structure-activity relationship; synthesis design.
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