Sensing macromolecular rearrangements in polymer networks by stimuli-responsive crosslinkers

A new family of azobenzene crosslinked brominated vinyl ester (DABA–BrVE) polymer networks was developed that exhibits reversible photochromic and fluorescence properties in which azobenzene serves as a crosslinker as well as a molecular sensor of structural and conformational changes of the surrounding macromolecular segments. The covalently “build-in” azobenzene crosslinker functions as a light emitting group capable of sensing stresses or damages, thereby altering photochromic and fluorescence properties. These reversible processes induced by structural network rearrangements may offer numerous application possibilities ranging from molecular stress sensors or nano-crack detectors in composites and other materials.