Lutfor, M. R. and Biswas, Tapan Kumar and Sarkar, Shaheen M. and M. M., Yusoff and Muhammad Nor Fazli, Abd Malek and Tschierske, Carsten (2015) New U-shaped Liquid Crystals Azobenzene Derived from Catechol for Photoswitching Properties. Journal of Molecular Liquids, 202. pp. 125-133. ISSN 0167-7322. (Published)
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Abstract
A new series of liquid crystals whose molecular structure consists of a U-shaped unit as a central core and two rod-like azobenzenes as the peripheral units are synthesized. The mesomorphic properties were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. The existence of nematic and smectic A phase was confirmed by textures and X-ray diffraction. The trans-form of azo compounds showed a strong band in the UV region at ~365 nm for the π–π* transition, and a weak band in the visible region at ~450 nm due to the n–π* transition. These molecules exhibit a strong photoisomerization behavior in which trans–cis take 50 and 55 s for compounds L4/5 and L4/6, respectively, whereas cis–trans take place almost 29 and 30 h, respectively. Long thermal back relaxation allows us to realize that optical storage devices with these materials which need longer periods.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Azobenzene; U-shaped; Smectic phase; Isomerisation; Photoswitching |
| Subjects: | Q Science > QD Chemistry |
| Faculty/Division: | Faculty of Industrial Sciences And Technology |
| Depositing User: | PM. Dr. Md. Lutfor Rahman |
| Date Deposited: | 09 Jan 2015 02:36 |
| Last Modified: | 14 Feb 2018 07:17 |
| URI: | http://umpir.ump.edu.my/id/eprint/8118 |
| Download Statistic: | View Download Statistics |
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