Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
Department of Chemistry and IRIS Adlershof, Humboldt-Universitat zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
Nat Commun. 2016 Jul 4;7:11975. doi: 10.1038/ncomms11975.
Nature provides much inspiration for the design of materials capable of motion upon exposure to external stimuli, and many examples of such active systems have been created in the laboratory. However, to achieve continuous motion driven by an unchanging, constant stimulus has proven extremely challenging. Here we describe a liquid crystalline polymer film doped with a visible light responsive fluorinated azobenzene capable of continuous chaotic oscillatory motion when exposed to ambient sunlight in air. The presence of simultaneous illumination by blue and green light is necessary for the oscillating behaviour to occur, suggesting that the dynamics of continuous forward and backward switching are causing the observed effect. Our work constitutes an important step towards the realization of autonomous, persistently self-propelling machines and self-cleaning surfaces powered by sunlight.
自然界为设计能够对外界刺激做出反应的运动材料提供了很多灵感，并且已经在实验室中创造了许多这样的主动系统的实例。然而，要实现由不变的恒定刺激驱动的连续运动，已经被证明是极其具有挑战性的。在这里，我们描述了一种掺杂有可见光响应的氟化偶氮苯的液晶聚合物薄膜，当暴露在空气中的阳光时，它能够进行连续的混沌振荡运动。同时受到蓝光和绿光的照射是发生振荡行为所必需的，这表明连续的前进和后退切换的动力学导致了观察到的效果。我们的工作是朝着实现由阳光驱动的自主、持续推进的机器和自清洁表面迈出的重要一步。
