Dendronized electrochromic polymer based on poly(3,4-ethylenedioxythiophene)

In order to improve electrochromic contrast, 3,4-ethylenedioxythiophene (EDOT) substituted with the first generation dendritic wedge based on gallic acid (M2) was synthesized by connecting 3,4,5-tribenzyloxy benzyl chloride to hydroxymethyl EDOT (M1). Electropolymerization of M1 and M2 resulted in the formation of an electroactive and well adhered film on the electrode surface. In the case of PEDOT substituted with the dendritic wedge (P2), it was observed that the resistance of the film increases with thickness. Spectroelectrochemical studies indicated that the polymers switch from a highly opaque dark-blue reduced state to highly transmissive oxidized state with a contrast of 67% in P2 and 46% in P1. In situ conductivity studies showed a sharp transition from a dedoped insulating state to doped conducting state at around −0.4 V with maximum in situ conductance of 0.06 S for P1 and 0.04 S for P2.