| Project/Area Number |
08405008
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied optics/Quantum optical engineering
|
|---|
| Research Institution | TOHOKU UNIVERSITY |
|---|
Principal Investigator |
HATTA Aritada Graduate School of Engineering, Tohoku University Professor, 大学院・工学研究科, 教授 (70005502)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Yushi Graduate School of Engineering, Tohoku University Lecturer, 大学院・工学研究科, 講師 (50236022)
WADAYAMA Toshimasa Graduate School of Engineering, Tohoku University Associate Professor, 大学院・工学研究科, 助教授 (20184004)
|
|---|
| Project Period (FY) |
1996 – 1998
|
| Project Status |
Completed (Fiscal Year 1998)
|
| Budget Amount *help |
¥12,500,000 (Direct Cost: ¥12,500,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1996: ¥7,500,000 (Direct Cost: ¥7,500,000)
|
|---|
| Keywords | liquid crystal / photoisomerization / molecular alignment / surface / IR spectroscopy / molecular alignment control / Raman scattering / vibrational spectroscopies / 配向制御 / 振動スペクトル / ラマン分光 |
|---|
| Research Abstract |
The photoisomerization of self-assembled monolayer films of 4-(4'-(methoxyphenylazo)phenoxy)undecane- 1-thiol (AZO 11) on evaporated gold films was investigated by means of Raman scattering and UV-visible and IR absorption measurements. The trans * cis photoisomerization of the self-assembled AZO11 molecules were restricted in comparison to the isomerization of AZO11 in solutions. Moreover, the trans-to-cis isomerization was more suppressed than the cis-to-trans isomerization, as expected from the molecular cross section of cis AZO11 that is larger than trans AZO11. On this basis we propose that cis-form samples are on the whole more suitable for cis trans photoisomerization in order to control the molecular alignment of liquid crystals. This indeed was verified in our experiments where thin films of a nematic liquid crystal (4-cyano-4'-pentylbiphenyl : 5CB) were deposited on the cis and trans AZO11 surface layers. IR reflection absorption spectroscopy revealed that 5CB molecules tend to align with their long axes perpendicular to the plane of the trans AZO11 layer. However, this alignment was affected by UV irradiation due to partial conversion to cis isomer. This fact demonstrates that liquid crystal alignment can be controlled by changes in the molecular shape on the substrate surface. Similar IR measurements were performed on gold film surfaces covered with a mixture of adsorbed AZO11 and hexadecanethiol (C_<16>H_<33>SH). in this case the limitation of AZO11 photoisomerization was relaxed and a larger change in the liquid crystal alignment was observed. The utility of IR transmission and Raman scattering measurements on silver island films was also demonstrated.
|
