Journal
LIQUID CRYSTALS
Volume 49, Issue 4, Pages 442-455Publisher
TAYLOR & FRANCIS LTD
DOI: 10.1080/02678292.2021.1975835
Keywords
Bent-core liquid crystal; 4-chloro-1; 3-diazobenzene; synthesis; nematic phase; photoisomerisation; molecular modelling; quantum mechanics calculations
Funding
- NSF [ACI-1445606, ACI1548562]
- National Natural Science Foundation of China [11074054,11374067]
Ask authors/readers for more resources
The synthesis of new compounds with azo functional groups and chlorine substituents in the central bent-cores has shown favorable mesogenic and photonic characteristics. Additionally, varying the carbon number in the terminal alkyl chains can alter the molecular dipole moment and affect the phase transition temperature and temperature range of the nematic phase.
A series of new compounds were synthesised by adding azo functional groups and chlorine substituent to the central bent-cores to form a 4-chloro-1,3-dizaophenylene bent-core. The structure, mesogenic properties, and photosensitivity of these compounds were characterised. The results show these synthesised compounds exhibit a broad temperature window up to 63.8 degrees C for nematic phase and the rapid rate of trans - cis photoisomerisation. For instance, at 95 degrees C, compound 4c in nematic phase became an isotropic liquid under UV-irradiation in 3 s and could be restored to nematic under natural visible light in 5 s. Quantum mechanics calculation confirms that using azos instead of esters as the central linkages can effectively reduce the molecular dipole moment, which appears to promote favourable mesogenic and photonic characteristics. Moreover, varying the carbon number in the terminal alkyl chains can alter molecular dipole moment and polarisability anisotropy, which are strongly correlated with the phase transition temperature and temperature range of the nematic phase. These findings suggest that 1) changing azo group position can effectively alter the intermolecular interactions by varying molecular polarity and polarisability; 2) reducing long-range electrostatic interactions can promote favourable mesogenic and possibly photonic properties of azobenzene bent-core liquid crystal.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available