稀土介孔-水凝胶纳米复合材料的共价键组装及光化学传感性质研究

The rare earth mesoporous materials possess excellent luminescent properties and high thermal stability, but there still exist some problems, such as non-uniform fluorescence, single color and fluorescence quench. Moreover, the existing form of powder materials have limited their applications to a large extent. Therefore the design and assembly of novel nanocomposite materials which can solve these problems and optimize their properties have important interest for the expansion of the application. In this project, based on the coordination chemistry and host-guest chemistry principles, through the co-assembly of rare earth mesoporous material and organogel, the nanocomposite materials with excellent mechanical and fluorescent sensing properties will be obtained. On the one hand, the rare earth mesoporous materials assembled with hydrogels will serve as junctions to enhance the mechanical and thixotropy properties of the hydrogels effectively; On the other hand, based on the energy transfer from organogel to rare earth luminophore, the nanocomposit materials will achieve optical signal output with the action of external field and display multi-color emissions due to introduction of sensing group. On this basis, the cooperative assembly mechanism and the dynamic driving behavior will be investigated; the energy and charge transfer mechanism between the rare earth mesoporous materials and the hydrogel as well as the luminescent behavior will be studied in the gel tissue; and the mechanism of response to external stimuli will be studied.

稀土介孔材料具有优异的发光性能及良好的热稳定性，但其也存在着发光不均匀、色相单一、容易淬灭等问题，而且其粉体材料的存在形式也极大地限制了它的应用，因此设计能和稀土介孔材料性能互补和优化的新型纳米复合材料无疑对于拓展这种材料的应用具有重大意义。本项目中，基于配位化学和主客体化学的基本原理，利用配位键作用将稀土介孔材料和有机小分子水凝胶构筑于同一基元中，以构建兼具凝胶态、优良力学性能和光化学传感性能的纳米复合材料。一方面，稀土介孔材料作为节点与凝胶聚集体的微观共组装可以有效地提高水凝胶的机械强度及触变性能；另一方面，基于凝胶基团和稀土发光基团之间的能量传递，通过引入传感基团，实现该复合材料对外场驱动的光学信号输出，并展示出丰富多彩的发光体系。在此基础上，将系统研究两种组分材料之间的协同组装、动态驱动行为以及能量转移机制；揭示复合材料对外界刺激的响应机制。

在国家自然科学基金“稀土介孔-水凝胶纳米复合材料的共价键组装及光化学传感性质研究”的资助下，我们开展了相关研究工作，并取得了阶段性成果。在本项目中，利用配位作用，将具有优异发光性能的稀土介孔材料和具有离子传感性能的有机小分子配体构筑于同一基元中，得到了一系列具有有序的介孔结构，高度的稳定性，优异的发光性能以及光化学传感性能的稀土介孔纳米复合材料。系统研究了不同介孔基质对于最终复合材料发光性能的研究，揭示了光化学传感的机理，探索了稀土和凝胶之间的能量传递机制，并且通过调控离子的量可以调控出不同波长的光，这些研究为新型稀土发光和传感材料的制备和研发提供了重要的理论基础。