Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light

The ability of light to alter/stabilize a particular thermodynamic phase is a power tool to investigate condensed matter from a new dimension. This field of photoinduced phase transitions is currently an important area of research. Being elastically soft and having subtle changes between its many ph...

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Main Authors:	Hegde, Gurumurthy, Prasad, S. Krishna, Nair, Geetha G.
Format:	Article
Language:	English
Published:	American Chemical Society 2007
Subjects:	QC Physics
Online Access:	http://umpir.ump.edu.my/id/eprint/5428/ http://umpir.ump.edu.my/id/eprint/5428/ http://umpir.ump.edu.my/id/eprint/5428/ http://umpir.ump.edu.my/id/eprint/5428/1/J_Phys_Chem_B_2007.pdf

id	ump-5428
recordtype	eprints
spelling	ump-54282018-05-18T02:06:05Z http://umpir.ump.edu.my/id/eprint/5428/ Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light Hegde, Gurumurthy Prasad, S. Krishna Nair, Geetha G. QC Physics The ability of light to alter/stabilize a particular thermodynamic phase is a power tool to investigate condensed matter from a new dimension. This field of photoinduced phase transitions is currently an important area of research. Being elastically soft and having subtle changes between its many phases a liquid crystal material is an attractive medium to investigate such light-driven phase transitions. The attraction is partly due to the large birefringence changes accompanying these transitions that are useful in developing photonic devices.In all of the cases reported to date, the photoinduced transition always leads to a phase that in any case exists in the thermal cycle. Recently we reported the first exception to such an established phenomenon (AdV. Mater. 2005, 17, 2086). The guest-host ternary mixture consisting of the photoactive azobenzene guest molecules does not exhibit smectic A phase in the absence of UV radiation. However, the smectic A phase is induced and stabilized only in the presence of UV light. In this paper, we map out hitherto unexplored temperature versus UV intensity phase diagrams for various mixtures, which illustrate that light mimics, in a limited sense, the role of a thermodynamic parameter such as, for example, pressure. The threshold UV intensity required to photodrive the appearance of the smectic A phase is seen to have a strong concentration dependence. Our studies also suggest the possibility of observing a double critical point by employing the UV intensity as a fine-tuning parameter. American Chemical Society 2007-01-18 Article PeerReviewed application/pdf en http://umpir.ump.edu.my/id/eprint/5428/1/J_Phys_Chem_B_2007.pdf Hegde, Gurumurthy and Prasad, S. Krishna and Nair, Geetha G. (2007) Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light. Journal of Physical Chemistry B, 111 (2). pp. 345-350. ISSN 1520-6106 (print); 1520-5207 (online) http://dx.doi.org/10.1021/jp066404g DOI: 10.1021/jp066404g
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Malaysia Pahang
building	UMP Institutional Repository
collection	Online Access
language	English
topic	QC Physics
spellingShingle	QC Physics Hegde, Gurumurthy Prasad, S. Krishna Nair, Geetha G. Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light
description	The ability of light to alter/stabilize a particular thermodynamic phase is a power tool to investigate condensed matter from a new dimension. This field of photoinduced phase transitions is currently an important area of research. Being elastically soft and having subtle changes between its many phases a liquid crystal material is an attractive medium to investigate such light-driven phase transitions. The attraction is partly due to the large birefringence changes accompanying these transitions that are useful in developing photonic devices.In all of the cases reported to date, the photoinduced transition always leads to a phase that in any case exists in the thermal cycle. Recently we reported the first exception to such an established phenomenon (AdV. Mater. 2005, 17, 2086). The guest-host ternary mixture consisting of the photoactive azobenzene guest molecules does not exhibit smectic A phase in the absence of UV radiation. However, the smectic A phase is induced and stabilized only in the presence of UV light. In this paper, we map out hitherto unexplored temperature versus UV intensity phase diagrams for various mixtures, which illustrate that light mimics, in a limited sense, the role of a thermodynamic parameter such as, for example, pressure. The threshold UV intensity required to photodrive the appearance of the smectic A phase is seen to have a strong concentration dependence. Our studies also suggest the possibility of observing a double critical point by employing the UV intensity as a fine-tuning parameter.
format	Article
author	Hegde, Gurumurthy Prasad, S. Krishna Nair, Geetha G.
author_facet	Hegde, Gurumurthy Prasad, S. Krishna Nair, Geetha G.
author_sort	Hegde, Gurumurthy
title	Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light
title_short	Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light
title_full	Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light
title_fullStr	Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light
title_full_unstemmed	Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light
title_sort	nonequilibrium liquid crystalline layered phase stabilized by light
publisher	American Chemical Society
publishDate	2007
url	http://umpir.ump.edu.my/id/eprint/5428/ http://umpir.ump.edu.my/id/eprint/5428/ http://umpir.ump.edu.my/id/eprint/5428/ http://umpir.ump.edu.my/id/eprint/5428/1/J_Phys_Chem_B_2007.pdf
first_indexed	2023-09-18T22:00:45Z
last_indexed	2023-09-18T22:00:45Z
_version_	1777414382109589504

Nonequilibrium Liquid Crystalline Layered Phase Stabilized by Light

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