过渡金属氧化物二维晶体材料的液晶化及有序宏观纤维组装

Two-dimensional crystals (i. e. nanosheets) possess many intriguing physical and chemical properties due to their unique infinite planar monolayer structure. For realizing the practical application of two-dimensional crystals, one possible and effective way is to assemble the two-dimensional monolayer units into macroscopic structure, for example, one-dimensional fiber. However, the documented macroscopic fiber of two-dimensional crystals has been limited to graphene (oxide) fiber, and the fiber on functional oxide sheets has been rarely reported, which should be blamed on the intrinsic low mechanic stiffness of metal oxides, only few hundredths of that for graphene. In our preliminary research, we developed a macroscopic fiber on titania sheets manifesting an unexpected high mechanical behavior even comparable to that for graphene fiber, owing to the formation of an unusual quasi-crystallographic ordered structure. But still there are many key scientific aspects that has not been explored and cleared. In this project, we will deeply study the nature of sheets, assembled fiber structure, fiber properties, and the relationship among them, the purpose of which is to ultimately grasp the hints for optimal construction of macroscopic architecture for general sheet materials. Possible use of the obtained fiber in portable devices will also be explored. The results of this project will open a new window onto making macroscopic fibers of general two-dimensional crystals with numerous functionalities, and bring promises to the realization of uses in practical devices.

二维晶体材料由于其独特的二维平面拓展结构具有众多优异的物理和化学性能。为了实现二维晶体材料的实际广泛应用，一个可能又有效的途径是把其组装成宏观尺度的材料，如一维纤维。但是目前二维晶体材料宏观纤维仅仅局限于石墨烯材料，而功能氧化物二维材料的宏观纤维却鲜见报道。这主要归咎于氧化物单片的机械性能非常差，仅有石墨烯材料百分之几的量级。在前期工作中我们发展了氧化钛二维材料的宏观纤维，其组装结构呈近晶体学有序的特征，因此机械性能几乎可以和石墨烯纤维相媲美。然而这项研究工作还有很多关键科学问题没有得到清楚的解释和阐明。本项目拟通过研究起始二维晶体材料本征特征、宏观纤维组装结构以及性能三者之间的关系，建立广泛意义上有序化组装规律和机制，并探讨在便携式纳米器件中的应用。该项研究对于二维晶体材料宏观纤维的结构设计和应用探索提供一种全新的思路和途径，将为二维晶体材料在现实器件中的应用注入新的活力。

将二维材料组装成宏观结构在基础科学和工业应用中均具有重要的意义，尤其将二维功能性氧化物材料液晶化并组装成宏观结构可赋予其丰富的功能性。本项目以二维氧化钛为主要研究对象，研究横向尺寸、厚度、表面等对是否形成液晶相的影响，探讨二维氧化钛表面对增强或解锁电化学存储特性的作用，进而发展有效组装宏观结构的方法以及器件结构，研究单体功能性在各种组装结构和器件中的集成作用机制，最终探索在智能柔性器件的应用。