Photo-induced phase transitions in azobenzene-doped liquid crystals

Legge, C.H. and Mitchell, G.R. (1992) Photo-induced phase transitions in azobenzene-doped liquid crystals. Journal of Physics D: Applied Physics, 25 (3). pp. 492-499. ISSN 1361-6463 doi: 10.1088/0022-3727/25/3/024

Abstract/Summary

The effect of irradiation (UV-visible light) on a nematic liquid crystal doped with a photoactive azobenzene derivative was investigated. The selective irradiation results in either an E implies Z or Z implies E isomerization of the azobenzene unit. The effect of the isomerization is to cause a reversible depression of the liquid crystal to isotropic (LC implies l) phase transition temperature of the doped mixture, which can be monitored optically as an isothermal phase transition. This depression also results in a biphasic liquid crystal+isotropic region which is discussed. The authors investigate the cause and magnitude of the phase depression as a function of the amount of doped 4-butyl-4'-methoxyazobenzene (photoactive unit) in 4-cyano-4'-n-pentylbiphenyl (liquid crystal unit), and as a function of the percentage conversion of E implies Z (caused by isomerization) in the azobenzene. The photostationary state of the doped mixtures achieved by Z implies E isomerization is considered and its effect upon the transition temperature of the mixture and response time of the system is discussed. They discuss the implications of the photostationary state with regards to the reversibility of the photo-induced phase transition and hence potential applications.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/26821
Item Type	Article
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) > Electron Microscopy Laboratory (CAF)
Publisher	IOP Publishing
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