Photoresponsive iodine-bonded liquid crystals based on azopyridine derivatives with a low phase-transition temperature |
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| Authors: | Meiling Du Luhai Li Jingting Zhang Kexuan Li Meijuan Cao Lixin Mo |
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| Institution: | 1. Institute of Macromolecules and Bioengineering, School of Materials Science and Engineering, North University of China, Taiyuan, People’s Republic of China;2. Beijing Engineering Research Center of Printed Electronics, Beijing Institute of Graphic Communication, Beijing, People’s Republic of China;3. College of Science, Xijing University, Xi’an, People’s Republic of China |
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| Abstract: | Halogen bonding interactions in the formation of liquid crystalline phases have been recognised in recent years. Here, we report a novel series of iodine-bonded liquid crystals using 1,2-diiodotetrafluorobenzene (1,2-DITFB) and azopyridine derivatives (AnAzPy), showing a smectic A phase and concurrent photoresponsive behaviour. These were characterised by using a polarising optical microscope, differential scanning calorimetry and UV-vis absorption spectroscopy. The formation of iodine bonding in the complexes was confirmed by X-ray photoelectron spectroscopy and Raman spectroscopy. Importantly, these iodine-bonded complexes demonstrated a low liquid crystal temperature range (30–50°C) among those reported for photoresponsive halogen-bonded liquid crystals. The molar ratio of the iodine-bonded donor and acceptor was 1:1 upon the self-assembly of the supramolecular complex molecule, as indicated by 1D-WAXD experiments of mixed samples of 1,2-DITFB and AnAzPy with different molar ratios. This study offers a new family of photoresponsive halogen-bonded liquid crystals and broadens the potential applications in their associated systems. |
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| Keywords: | Halogen-bonding azopyridine photoresponsive liquid crystal low phase-transition temperature |
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