微梁阵列--拉曼光谱联用系统设计及偶氮苯材料光响应过程中产生的应力机理研究

The cis-trans isomerization transformation is a common method for the conversion of light energy into mechanical energy for an azo polymers material film. However, a single measurement can hardly explain the cause of surface tension in the conversion process. Raman spectroscopy can be used to characterize the advantages of the material structure，so the combination system of the microcantilever array system and Micro-Raman spectroscopy was built in this application to realize real-time in-situ detection of structural and surface mechanical properties of azo polymers material during light energy and mechanical conversion. The free end of the cantilever, by means of the translational reciprocation of the microcantilever array, was scanned by laser. On top of the other side of the microcantilever, a micro-Raman, a single-pass video acquisition module and an ultraviolet light irradiation module were set up. This system is used to realize the real-time in-situ characterization of micro molecular structure and surface stress during cis-trans isomerization of azo polymers under UV light irradiation, and the relationship between the microstructure change process and surface mechanics is also studied. The density functional theory is used to simulate and analyze the geometric structure and mechanical properties of azo polymers, and the theoretical structure is combined with the actual structure and mechanical galaxy mentioned above to explore the mechanism of stress generation. According to the above mechanism, a new type of azobenzene composite materials are designed and controllable light control actuators can be prepared. The construction of the combined system will help to study the mechanism of photo-mechanical energy conversion in photoisomerization, and also provide theoretical support for the design of controllable light control actuators.

顺反异构转变是偶氮苯类材料实现光能转化为机械能的常见手段。但非实时、原位和单一的测试难解释这一动态过程中应力产生的原因。本申请拟通过搭建显微拉曼光谱和微梁阵列传感器联用的新型检测系统，对顺反异构化过程中结构和应力的关系进行研究。通过微梁阵列的往复平动实现激光对梁自由端的相对往复一维运动；在梁另一侧上方，添加显微拉曼光谱模块、单筒显微视频观察模块和紫外/可见光照射模块；利用该系统实现在紫外/可见光照射下分子结构和表面应力的表征；利用分子动力学和密度泛函理论对偶氮苯的顺反异构化过程和几何结构进行模拟分析。结合实验结果和模拟分析，研究这类新颖材料的结构和力学性能的关系，探讨由于结构变化产生应力的机理。并利用上述机理设计新型偶氮苯复合材料并制备光控促动器。该联用系统的搭建和机理的研究，有助推动对光响应过程机理进行深入探讨，也为相关的催化和降解等界面问题提供一种新的研究手段。

光响应智能高分子材料的开发利用是材料领域研究的热点之一。在光驱动材料中，含偶氮苯结构的聚合物是光响应性聚合物体系中的典型代表。在紫外光照射下，偶氮苯基团会从反式转变为顺式状态（trans→cis），整个异构化过程循环可逆。偶氮苯材料顺反异构的变化是实现将光能直接转化为机械能的一个常见手段。在本项目研究中，首先搭建了一套微梁阵列-拉曼光谱联用系统，实现了在紫外光照射下对偶氮聚合物顺反异构化过程中微观分子结构和表面应力的原位实时表征。研究中对材料进行了应力-距离曲线的测试，得到了液相和固相的数据，发现可固液转变的偶氮苯聚合物的表面张力的变化与不可固液转变的有很大的不同；紫外光下其表面张力变化呈现的先下降再上升，再下降至平衡的趋势。实验表明，偶氮苯材料的良好的重复循环特性以及光强越强变化越大的稳定变化规律将对光控致动器和可调控表面活性剂的研究提供很大的助力，也拓展了微悬臂梁传感器的用途，为光响应物质分析处理提供了一种新的方式。.此外在本项目的资助下，还利用微悬臂梁传感技术进行了固液界面间横向摩擦力的研究工作，制备了不同的SERS基底来对有机染料进行检测以及制备了Janus膜按需进行油水乳液分离。