Date

Place

Room G (Room 306)
40. Synthetic LCs
August 20, 2015 (Thursday)
15:30 ~ 16:35

[40-3]
16:20 ~ 16:35
Title:Synthesis of Bent-Shaped Liquid Crystals for Photoswitchable Properties
Md Lutfor Rahman, Mashitah Md Yusoff, Shaheen Md Sarkar (Univ. Malaysia Pahnag, Malaysia), Sandeep Kumar (Raman Research Inst., India), and Carsten Tschierske (Martin Luther Univ. Halle, Germany)
Abstract: Three series of liquid crystalline compounds comprised of bent-shaped molecules derived from some cores molecules such as resorcinol (series I), pyrimidine (series II) and naphthalene (series III) cores incorporating azobenzene in the side arms, and having terminal double bonds as polymerizable functional groups, were synthesized and characterized by polarized-light optical microscopy (POM) and X-ray diffraction analysis. Series I having bent core compounds exhibited intercalated smectic (B6) phase and rectangular columnar (B1) phases. Series II also having bent core compounds with lower homologues compounds are crystalline in nature whereas higher homologues compounds display stable enantiotropic B6 phase. Series III have bent-shaped shaped compounds with lower homologues compound show nematic phase while higher homologues compounds exhibit B6 phase. These bent-shaped molecules exhibited strong photoisomerisation behaviour in solutions and solid state. The photoswitching properties of series I and III show trans to cis isomerization ranging 9 - 15 seconds, whereas reverse process takes place 160 - 380 min. In case of solid film, E-Z photoisomerization takes around 4 sec and reverse transformation to original Z-E state takes about 70 min. Thus, the photoswitching behaviour of these materials may be suitably exploited in the field of optical data storage device and in molecular switches.
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