响应性二维胶体晶体亚微米薄膜的制备及光学传感性质研究

Last decade has seen a growing interest in exploiting colloidal crystals, which are long-range ordered arrays of monodisperse colloidal particles, as signal transducers for the application in optical sensing and detections. So far, most colloidal crystal-sensing motifs have been fabricated from three-dimensional (3D) colloidal crystals, yet such 3D motifs have encountered challenges in achieving fast responses and low detection limits, which are very likely restricted by their relatively thick structures and large volumes. Two-dimensional (2D) colloidal crystals and their derived structures usually take the form of sub-micron thin films with interconnected macropores. Such sub-micron structures may not only enhance rapid diffusions of analytes (especially when they are in the form of solutes), but also enable detections of small volumes or quantities, and hence can greatly help improving the sensors' performance on the response time and the detection limit; moreover, 2D colloidal crystals have shown more diverse and sensitive optical properties comparing with their 3D counterparts, whereas their fabrication and processing are even less complicated. This research project is intended to fabricate responsive sub-micron thin films from 2D colloidal crystals and study their optical sensing properties. By using chemical synthesis, functional modification and self-assembly, responsive or functional materials, such as polymer gels, microporous materials and functional groups or molecules will be incorporated into the frameworks of 2D colloidal crystals so as to obtain sub-micron thin films with both specific responsiveness and optical properties resulting from 2D ordered structures. Then the optical properties of the as-fabricated responsive sub-micron thin films, including the visible light transmission and reflectance, the 3D distribution of electromagnetic wave and related resonance modes will be studied by optical measurement as well as theoretical simulation. Meanwhile，the effect from composing materials' properties and structural parameters on the optical properties of the as-fabricated sub-micron thin films will be elucidated, which is of great significance to the development of sensing motifs based on 2D colloidal crystals. After optimizing the optical properties and structures, sensing motifs of 2D colloidal crystal-based sub-micron thin films targeted for specific chemical or biological analytes will be constructed and their performances will be thoroughly tested by investigating the response time, detection limit, sensitivity and selectivity. Furthermore, in situ detection using these sensing motifs will be conducted and corresponding sensors and sensing chips will be produced. Via this research project, versatile and high-performance sensing motifs based on 2D colloidal crystals that overcome problems of their 3D counterparts will be developed, which will make a contribution to label-free optical sensing and detections.

自组装胶体光子晶体在光学传感领域有重要应用前景，但传统三维胶体晶体传感结构在响应速率和检测限方面面临挑战,而二维胶体晶体以其亚微米的薄膜结构和特殊的光学性质在光学传感中有潜在应用优势。本项目拟开展响应性二维胶体晶体亚微米薄膜的制备及光学传感性质研究，通过化学合成、功能修饰、自组装等"自下而上"的手段在二维胶体晶体中引入响应性或功能性物质,如聚合物凝胶、微孔材料、功能基团或分子等，获得具有特定响应性的二维胶体晶体亚微米薄膜；通过光学测量和理论模拟相结合的方式研究所制备的二维胶体晶体亚微米薄膜的光学性质，明晰组成物质的本征特性及介观结构对薄膜光学性质的影响和作用规律；以几类代表性物质为检测对象，研究所制备的响应性二维胶体晶体亚微米薄膜的光学传感性能，认知制约其传感性能提高的因素，构建响应速率快、灵敏度高、检测限低，适用于原位、非侵入式检测的新型高性能光学传感模型，推动无标光学传感检测的发展。

自组装胶体光子晶体在光学传感领域有重要应用前景，但传统三维胶体晶体传感结构在响应性、响应速率和检测限等重要性能上面临挑战,而二维胶体晶体以其亚微米的薄膜结构和特殊的光学性质在光学传感应用中显示出潜在优势。本项目研究响应性二维胶体晶体亚微米薄膜的制备及光学传感性质，通过化学合成、功能修饰、自组装等"自下而上"的手段在二维胶体晶体中引入响应性或功能性物质,如聚合物凝胶、微孔材料、功能基团或分子等，获得具有特定响应性的二维胶体晶体亚微米薄膜；通过光学测量和理论模拟相结合的方式研究所制备的二维胶体晶体亚微米薄膜的光学性质，明晰组成物质的本征特性及介观结构对薄膜光学性质的影响和作用规律；以几类代表性物质为检测对象，研究所制备的响应性二维胶体晶体亚微米薄膜的光学传感性能，认知制约其传感性能提高的因素。通过以上研究，成功构建了几种性能优异的基于二维胶体晶体的亚微米光学薄膜，主要包括：用于蒸气传感的超薄微孔材料薄膜包覆的二维胶体晶体光学薄膜；用于传感和分离的二维有序大孔微孔材料薄膜；用于快速色度化学传感的高分子凝胶填充的二维胶体晶体薄膜；用于检测挥发性有机物的高性能微孔材料空心球壳阵列光学传感薄膜。所构建的亚微米光学传感薄膜显示出响应快、灵敏度高、检测限低、肉眼可辨、原位非侵入等优点，是一类新型的高性能光学传感模型，对推动无标光学传感检测的研究发展具有显著的科学意义。