Mechanical Motion of Azobenzene Crystals upon Photoirradiation

作者：Hideko Koshima, Naoko Ojima, Hidetaka Uchimoto · 发表于：Journal of the American Chemical Society · 年份：2009 · DOI：10.1021/ja8098596 · 被引用次数：508 · 研究领域：Photochromic and Fluorescence Chemistry、Advanced Materials and Mechanics、Liquid Crystal Research Advancements

Photomechanical bending of trans-4-(dimethylamino)azobenzene microcrystals was observed. Upon UV irradiation, the (001) face of the platelike microcrystals bent quickly in the direction opposite the light source, reaching the maximum deflection after 0.5 s. The microcrystal returned to its initial flat shape 30 s after the illumination was stopped. This mechanical motion was reversible over repeated cycles of UV irradiation. The bending effect was attributed to a gradient in the extent of UV-induced trans-cis photoisomerization as a function of light penetration, causing the expansion of the irradiated crystal surface along the b axis to result in a bent macrostructure.