Modulating the Properties of Azulene-Containing Polymers through Controlled Incorporation of Regioisomers

• Published in: Advanced functional materials 2014-12, Vol.24 (46), p.7338-7347
• Main Authors: Tsurui, Kazuhiko, Murai, Masahito, Ku, Sung-Yu, Hawker, Craig J., Robb, Maxwell J.
• Format: Article
• Language: English
• Subjects: Azulene; Color; conjugated polymers; Design engineering; Optoelectronics; Polymers; regioisomers; stimuli-responsive materials; Strategy; Thin films; Tuning
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201402554

Two libraries of random conjugated polymers are presented that incorporate varying ratios of regioisomeric azulene units connected via the 5‐membered or 7‐membered ring in combination with bithiophene or fluorene comonomers. It is demonstrated that the optoelectronic and stimuli‐responsive properties of the materials can be systematically modulated by tuning the relative percentage of each azulene building block in the polymer backbone. Significantly, these materials exhibit stimuli‐responsive behavior in the solid state with spin‐coated thin films undergoing rapid and reversible color switching. Ultimately, this work introduces a new design strategy in which the optoelectronic properties of conjugated polymers can be modulated by varying only the regiochemistry of the constituent building blocks along a polymer chain. Tuning the percentage of azulene regioisomers in conjugated polymers leads to systematic variation in optoelectronic properties. A new design strategy in which the properties of conjugated polymers can be modulated by simply varying the regiochemistry of the building blocks along the polymer chain is demonstrated. Significantly, these materials exhibit ­stimuli‐responsive behavior in the solid state with thin films undergoing rapid and reversible color switching.