Reactive Strand Extension to Improve Stretchability in Semiconducting Polymers

As electronics become more seamlessly integrated into our everyday lives, the demand for durable, stretchable, and electron-conducting materials will continue to grow. However, many conductive materials suffer from poor electrical performance under repeated mechanical strain, which limits their lifetime use. Inspired by developments to enhance stretchability in nonconjugated materials with covalent mechanochemistry, we explore reactive strand extension (RSE) as a strategy to mitigate poor electronic performance in conjugated polymer semiconductors under strain. Herein, we incorporated RSE into a donor–acceptor conjugated polymer by copolymerizing cinnamate dimers into the conjugated backbone and evaluated their impact on stretchability. RSE was found to improve stretchability in cross-linked conjugated polymer systems via crack onset strain measurements, atomic force microscopy, dichroic ratio measurements, and grazing-incidence wide-angle X-ray scattering. Lastly, charge carrier mobility measurements from organic field-effect transistors revealed that RSE-containing cross-linked conjugated polymers retained mobility more effectively under mechanical strain compared to unmodified conjugated polymers. Overall, our study presents an alternative strategy to improve the performance of conjugated polymers for stretchable electronics.