Department of Chemistry, University of California, 501 Big Springs Road, Riverside, CA 92521, USA.
Nanoscale. 2018 Feb 15;10(7):3393-3398. doi: 10.1039/c7nr09571f.
Crystalline nanowires composed of the photochromic diarylethene derivative 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene (1a) are prepared and characterized. 200 nanometer diameter wires with a length of 60 microns are grown by slow solvent annealing in a porous anodic aluminum oxide template. The nanowires are oriented crystals, as determined by X-ray diffraction measurements, and can be liberated by dissolving the template in acid. They exhibit pronounced bending when exposed to ultraviolet light that can be reversed by visible light irradiation. The bending-unbending sequence can be repeated for more than 10 cycles without fatigue. This robustness results from the ability of the nanowires to maintain their crystallinity during the forward and reverse reactions. The small diameter of these nanowires allows them to achieve curvatures that are at least 40 times greater (200 mmversus 5 mm) than those observed for micron-thick diarylethene needles. This first demonstration of photomechanical nanostructures based on diarylethene photochromism opens up the possibility of making more complicated structures composed of this high-performance photochrome.
由光致变色二芳基乙烯衍生物 1,2-双(2,4-二甲基-5-苯基-3-噻吩基)全氟环戊烯(1a)组成的晶须被制备并进行了表征。通过在多孔阳极氧化铝模板中缓慢溶剂退火，生长出直径为 200 纳米、长 60 微米的纳米线。X 射线衍射测量确定纳米线为取向晶体，并可以通过在酸中溶解模板来释放。它们在暴露于紫外光时表现出明显的弯曲，这种弯曲可以通过可见光照射来逆转。弯曲-伸直的序列可以重复超过 10 次而不会疲劳。这种稳健性源于纳米线在正向和反向反应过程中保持其结晶度的能力。这些纳米线的小直径使得它们能够达到的曲率至少比观察到的微米厚二芳基乙烯针的曲率大 40 倍(200mm 与 5mm)。基于二芳基乙烯光致变色的光机械纳米结构的首次演示为制造由这种高性能光致变色材料组成的更复杂结构开辟了可能性。
