BROWSE

Related Researcher

Author's Photo

Park, Lee Soon
School of Materials Science and Engineering
Research Interests
  • Flexible OLED new materials, process and fabrication
  • Touch Screen Panel(TSP) new materials and process new materials and process
  • Nano-materials synthesis and application (Ag nano-wire and metal mesh electrode)

ITEM VIEW & DOWNLOAD

Photoinduced phase transition of nematic liquid crystals with donor-acceptor azobenzenes: mechanism of the thermal recovery of the nematic phase

Cited 26 times inthomson ciCited 30 times inthomson ci
Title
Photoinduced phase transition of nematic liquid crystals with donor-acceptor azobenzenes: mechanism of the thermal recovery of the nematic phase
Author
Tsutsumi, OKanazawa, AShiono, TIkeda, TPark, Lee Soon
Keywords
article; chemical structure; laser; light; liquid crystal; phase transition; photochemistry; stereoisomerism; temperature
Issue Date
1999-09
Publisher
ROYAL SOC CHEMISTRY
Citation
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, v.1, no.18, pp.4219 - 4224
Abstract
Photoinduced nematic (N)-to-isotropic (I) and thermal I-N phase transition behaviour of liquid crystals (LCs) with donor-acceptor azobenzenes was investigated. Photoirradiation of mixtures of the azobenzenes and host LC resulted in N-I phase transition due to trans-cis photoisomerisation of the azobenzenes, and the N phase recovered when the irradiated sample was kept in the dark because of thermal cis-trans back-isomerisation. Time-resolved measurements with a laser pulse (355 or 532 nm; 10 ns fwhm) revealed that the photoinduced N-I phase transition took place within 200-300 mu s in all samples. The rate of the thermal I-N phase transition was affected strongly by the strength of the donor and the acceptor. The response time of the thermal I-N phase transition corresponded closely to the lifetime of the cis isomer of the azobenzenes, hence we can conclude that the rate-determining step of the thermal recovery of the N phase was the cis-trans isomerisation process. The time necessary for the thermal I-N phase transition decreased with increasing donor and acceptor strength, because the thermal cis-trans isomerisation of the azobenzene with a stronger donor-acceptor pair became faster. The N phase recovered within 500 ms in the mixture of the azobenzene (with tertiary amine as the donor and nitro group as the acceptor) and host LC at 37 degrees C
URI
Go to Link
DOI
10.1039/a905172d
ISSN
1463-9076
Appears in Collections:
MSE_Journal Papers
Files in This Item:
a905172d.pdf Download

find_unist can give you direct access to the published full text of this article. (UNISTARs only)

Show full item record

qrcode

  • mendeley

    citeulike

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

MENU