Department of Materials Chemistry, Faculty of Science and Technology, Ryukoku University, Seta, Otsu, 520-2194, Japan.
Department of Chemistry, Asahikawa Medical University, 2-1-1-1 Midorigaoka-higashi, Asahikawa, Hokkaido, 078-8510, Japan.
Chemistry. 2018 Jun 18;24(34):8491-8506. doi: 10.1002/chem.201705427. Epub 2018 Mar 30.
Photoresponsive crystalline systems mimicking bio-functions are prepared using photochromic diarylethenes. Upon UV irradiation of the diarylethene crystal, the photogenerated closed-ring isomers self-aggregate to form needle-shaped crystals on the surface. The rough surface shows the superhydrophobic lotus effect. In addition, the rose-petal effects of wetting, the anti-reflective moth-eye effect, and a double-roughness structure mimicking the surface of a lotus leaf are observed by controlling the heating procedures, UV irradiation processes, and molecular structural modification. By changing the molecular structure, a superhydrophilic surface mimicking a snail shell can be generated. We also find the crystal of a diarylethene derivative that shows a photosalient effect. The effect is observed partly due to the hollow structure of the crystal. It is demonstrated that a photo-response similar to the response of impatiens plant to stimulation is observed by packing small beads in the hollow. These photoresponsive functions are unique, and they demonstrate a macroscopic response by means of microscopic molecular movement induced by light. In the future, such a molecular assembly system will be a promising candidate for fabricating photoresponsive architectures and soft robots.
采用光致变色二芳基乙烯制备模拟生物功能的光响应晶态体系。二芳基乙烯晶体受到紫外光照射时，光致闭环异构体自组装在表面形成针状晶体。粗糙的表面呈现出超疏水的莲花效应。此外，通过控制加热程序、紫外光辐照过程和分子结构修饰，可以观察到润湿的玫瑰花瓣效应、抗反射蛾眼效应以及模仿荷叶表面的双重粗糙度结构。通过改变分子结构，可以生成模拟蜗牛壳的超亲水表面。我们还发现了一种显示出光致突跃效应的二芳基乙烯衍生物晶体。这种效应部分是由于晶体的中空结构引起的。实验表明，通过在中空部分填充小珠子，可以观察到类似于凤仙花植物对刺激的光响应。这些光响应功能是独特的，它们通过光诱导的微观分子运动表现出宏观响应。在未来，这种分子组装体系有望成为构建光响应结构和软机器人的候选材料。
