Light-Controlled Friction by Carboxylic Azobenzene Molecular Self-Assembly Layers.
Light-Controlled Friction by Carboxylic Azobenzene Molecular Self-Assembly Layers.
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羧基偶氮苯分子自组装层的光控摩擦
DOI：
10.3389/fchem.2021.707232
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发表时间：
2021
影响因子：
5.5
通讯作者：
Luo J
中科院分区：
文献类型：
--
作者：
Xue D;Ma L;Tian Y;Zeng Q;Tu B;Luo W;Wen S;Luo J
如今，可逆摩擦调控已成为科学家们在感光材料柔性调控结构和理论方面关注的焦点，促进了该领域的快速发展。同时，光作为一种外部刺激，在时空控制和远程触发方面具有巨大的潜力和优势。在这项工作中，我们展示了两个光异构化有机分子层，四羧基偶氮苯（NN4A）和二羧基偶氮苯（NN2A），选择它们在高取向热解石墨（HOPG）表面构建模板网络来研究摩擦性能，对应于光调节下自组装层的排列结构。首先，通过扫描隧道显微镜（STM）对自组装层的形貌进行表征，然后通过原子力显微镜（AFM）测量模板网络的纳米摩擦学性能。在光照控制下，它们的摩擦系数分别变化约0.6倍和2.3倍。采用密度泛函理论（DFT）方法计算了光调节下自组装系统的力强度与摩擦特性之间的关系。在此，外部光刺激的使用在调节纳米界面的摩擦特性方面发挥着重要作用，有望为未来先进表面器件制造的进一步光控研究奠定基础。
Nowadays, reversible friction regulation has become the focus of scientists in terms of the flexible regulatory structure of photosensitive materials and theories since this facilitates rapid development in this field. Meanwhile, as an external stimulus, light possesses great potential and advantages in spatiotemporal control and remote triggering. In this work, we demonstrated two photo-isomerized organic molecular layers, tetra-carboxylic azobenzene (NN4A) and dicarboxylic azobenzene (NN2A), which were selected to construct template networks on the surface of the highly oriented pyrolytic graphite (HOPG) to study the friction properties, corresponding to the arrangement structure of self-assembled layers under light regulation. First of all, the morphology of the self-assembled layers were characterized by a scanning tunneling microscope (STM), then the nanotribological properties of the template networks were measured by atomic force microscope (AFM). Their friction coefficients are respectively changed by about 0.6 and 2.3 times under light control. The density functional theory (DFT) method was used to calculate the relationship between the force intensity and the friction characteristics of the self-assembled systems under light regulation. Herein, the use of external light stimulus plays a significant role in regulating the friction properties of the interface of the nanometer, hopefully serving as a fundamental basis for further light-controlling research for the future fabrication of advanced on-surface devices.