Jelken Joachim, Santer Svetlana
Institute of Physics and Astronomy, University of Potsdam 14476 Potsdam Germany
RSC Adv. 2019 Jun 28;9(35):20295-20305. doi: 10.1039/c9ra02571e. eCollection 2019 Jun 25.
In this paper we report on photoswitchable polymer surfaces with dynamically and reversibly fluctuating topographies. It is well known that when azobenzene containing polymer films are irradiated with optical interference patterns the film topography changes to form a surface relief grating. In the simplest case, the film shape mimics the intensity distribution and deforms into a wave like, sinusoidal manner with amplitude that may be as large as the film thickness. This process takes place in the glassy state without photo-induced softening. Here we report on an intriguing discovery regarding the formation of reliefs under special illumination conditions. We have developed a novel setup combining the optical part for creating interference patterns, an AFM for acquisition of topography changes and diffraction efficiency signal measurements. In this way we demonstrate that these gratings can be "set in motion" like water waves or dunes in the desert. We achieve this by applying repetitive polarization changes to the incoming interference pattern. Such light responsive surfaces represent the prerequisite for providing practical applications ranging from conveyer or transport systems for adsorbed liquid objects and colloidal particles to generation of adaptive and dynamic optical devices.
在本文中，我们报道了具有动态可逆起伏形貌的光开关聚合物表面。众所周知，当用光学干涉图案照射含偶氮苯的聚合物薄膜时，薄膜形貌会发生变化以形成表面起伏光栅。在最简单的情况下，薄膜形状模仿强度分布，并以波状、正弦方式变形，其振幅可能与薄膜厚度一样大。这个过程在玻璃态下发生，没有光致软化现象。在此，我们报道了关于在特殊光照条件下起伏形成的一个有趣发现。我们开发了一种新颖的装置，它结合了用于产生干涉图案的光学部件、用于获取形貌变化的原子力显微镜以及衍射效率信号测量装置。通过这种方式，我们证明这些光栅可以像水波或沙漠中的沙丘一样“运动起来”。我们通过对入射干涉图案施加重复的偏振变化来实现这一点。这种光响应表面是提供实际应用的先决条件，这些应用范围从用于吸附液体物体和胶体颗粒的输送或运输系统到自适应和动态光学器件的产生。
