| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 가을 (10/13 ~ 10/14, 제주 ICC) |
| 권호 | 30권 2호 |
| 발표분야 | 분자전자 부문위원회 |
| 제목 | Light-driven polymeric mass migration of azopolymer films: effects of photoexcitation wavelength and polarization state |
| 초록 | Surface relief grating (SRG) on azobenzene polymer films can be fabricated under an irradiation with interference pattern of laser due to light-driven mass migration of the polymer.1-3 The molecular mobility rises from trans-cis-trans photoisomerization cycles of azobenzenes at room temperature. In this work, the dynamics of SRG formation was examined on methacrylate-based azopolymers by turning photoexcitation wavelengths of laser in visible region. As increasing the excitation wavelength close to n-π* transition of azobenzenes, the rate rapidly increased. By theoretical studies, it is suggested that the photoisomerization pathway is determined by a competition of photoexcitation from trans and relaxation to cis, and the n-π* channel give the fast relaxation pathway in the system. In the second part of this talk, we will present the dynamic effect on the polarization states examined in thin azopolymer films. As decreasing the film thickness lower than 100 nm, the speed of SRG formation was dramatically suppressed, and the photoinduced surface structures were strongly responding to the polarization states, not simply sinusoidal patterns with small depth. The mechanism of photoinduced SRG formation will be suggested as the photoinduced supramolecular assembly of azobenzene segments which were initially aligned perpendicularly to the incident polarization direction of laser. References: 1. D. Y. Kim, S. K. Tripathy, L. Li, J. Kumar, Appl. Phys. Lett. 66, 136 (1995). 2. Sekkat, W. Knoll, Photoreactive organic thin films, Elsevier Science, 2002, ch. 14. 3. M. J. Kim, E. M. Seo, D. Vak, D. Y. Kim, Chem. Mater. 15, 4021 (2003) |
| 저자 | 김미정1, 이재동1, 김재현2, Seiji Higuchi1, 김동유3, Tomonobu Nakayama1 |
| 소속 | 1National Institute for Materials Science, 2Samsung electronics, 3광주과학기술원 |
| 키워드 | surface relief grating; azopolymer; photoinduced orientation |
