Preparation and Electrochromic Properties of a Spiral Bridge Modified Conjugated Polymer Based on Fused‐Rings

ABSTRACT Fused‐ring‐based conjugated polymers possess unique advantages such as a broad optical absorption region and high charge transport ability. In this work, a spiral bridge modified fused‐ring monomer (spiro‐IDT) was synthesized and further polymerized to form the corresponding conjugated polymer, poly(spiro‐IDT), using an electrochemical method. The optical and electrochemical properties of spiro‐IDT and poly(spiro‐IDT) were measured carefully. Because of its large conjugated ring, spiro‐IDT could be polymerized under a low potential of 0.96 V. Scanning electron microscopy (SEM) results demonstrated that the poly(spiro‐IDT) film possessed a porous surface morphology. Poly(spiro‐IDT) underwent a reversible color change between orange and light purple at a fast response time (oxidation: 1.1 s; reduction: 0.3 s). These results indicate that spiral ring modified conjugated polymers based on fused‐rings possess electrochromic properties and that the spiral bridge structure may be beneficial for improving response times of conjugated polymer.