Effect of Surface Properties on the Photo-Induced Crawling Motion of Azobenzene Crystals on Glass Surfaces.
Effect of Surface Properties on the Photo-Induced Crawling Motion of Azobenzene Crystals on Glass Surfaces.
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DOI：
10.3389/fchem.2021.684767
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发表时间：
2021
影响因子：
5.5
通讯作者：
Takada N
中科院分区：
文献类型：
--
作者：
Norikane Y;Hayashino M;Ohnuma M;Abe K;Kikkawa Y;Saito K;Manabe K;Miyake K;Nakano M;Takada N
研究了3，3‘-二甲基偶氮苯(DMAB)晶体在不同表面性质的玻璃衬底上的光致爬行运动。当同时暴露在来自不同方向的紫外光和可见光下时，晶体在玻璃表面上不断爬行。在亲水表面，晶体的爬行速度比其他表面的要快，但晶体在移动时会扩散。另一方面，在疏水表面，晶体的形状变化不大，爬行速度较慢。DMAB在表面修饰的玻璃基板上的液相接触角与水的接触角呈正相关。熔融偶氮苯与玻璃表面的相互作用对爬行运动起着重要的作用。我们提出了模型来解释导致定向运动的不对称条件。具体地，通过考虑紫外光和可见光的穿透长度，成功地证明了光在晶体位置的穿透深度是不同的。这造成了一种非平衡状态，熔化和结晶在同一晶体中占主导地位。
Photo-induced crawling motion of a crystal of 3,3′-dimethylazobenzene (DMAB) on a glass substrate having different surface properties was studied. When exposed to UV and visible lights simultaneously from different directions, crystals crawl continuously on a glass surface. On a hydrophilic surface, the crystals crawled faster than those on other surfaces but crystals showed spreading while they moved. On hydrophobic surfaces, on the other hand, the crystals showed little shape change and slower crawling motion. The contact angles of the liquid phase of DMAB on surface-modified glass substrates showed positive correlation with the water contact angles. The interaction of melted azobenzene with glass surfaces plays an important role for the crawling motion. We proposed models to explain the asymmetric condition that leads to the directional motion. Specifically by considering the penetration length of UV and visible light sources, it was successfully shown that the depth of light penetration is different at the position of a crystal. This creates a nonequilibrium condition where melting and crystallization are predominant in the same crystal.