Polymers that exhibit a mechanical response to external stimuli are technologically important. Here, a polymer is described that shows a very large negative thermal expansion on heating or irradiation with near-infrared light. This property is stable over hundreds of cycles and is shown to be driven by a conformational change of an s-dibenzocyclooctadiene unit within the polymer structure.
- Xingyuan Shen
- Christopher Viney
- Jennifer Q. Lu
