At the Organic Materials Unit we introduce a unique liquid crystal elastomer (LSCE) incorporating a carbazole-based fluorophore linked to an indolenine, either directly or via a double bond. This innovative material exhibits positive mechanofluorescence when subjected to stretching. We propose that this behavior arises from an increase in the microviscosity of the LSCE during stretching, causing the constituent mesogens or molecules to draw closer. This proximity enhances the interaction between the fluorophore and mesogen. Notably, the fluorophore connected via a double bond displays lower fluorescence compared to the direct linkage, likely attributed to increased energy dissipation due to rotational effects when the fluorophore is excited. This material holds promise for future applications requiring tactile feedback devices.
Programming Positive Mechanofluorescence in Liquid Crystalline Elastomers
Pedro Güixens-Gallardo, Ignacio Brea, Jordi Manrique, Farhad Shohraty, Jaume Garcia-Amorós*, and Dolores Velasco*. ACS Appl. Polym. Mater. 2023, 5, 8, 6484–6492