锂皂石为框架基质的光控可逆超分子有机-无机杂化水凝胶的构筑

Recently, the construction of reversible and controllable intelligent material by supramolecular self-assembly have attracted growing interest in the fields of material science and life science. However, materials with intermolecular weak interactions as drive force usually softness and show poor mechanical property, which has limited its applications in some special fields. The objective of this project is to design and construct novel organic-inorganic hybrid hydrogel with the feature of both high mechanical property and good reversibility by combination of supramolecular macrocyclic host-guest interaction and inorganic substrate. The introduction of laponite as scaffolds will effectively improve the mechanical strength of the gel while supramolecular noncovalent interaction gives the system excellent controllability and reversibility. Controllable and reversible sol-gel process will be achieved based on the photoisomerization of azophenyl moiety under light irradiation. In addition, the mechanism, control factor and drive force of this macroscopic self-assembly process will be expounded in detail by determining thermodynamic parameters and dynamic parameters. The mechanical properties of this hybrid hydrogel will be investigated by measuring the viscous coefficient and elastic coefficient. This study will provide theory and technology for fabricating high mechanical strength and bio-compatible hydrogel. Furthermore, our research play very important role in fundamental scientific research and a variety of application in the fields of biological material for filling, photo-responsive devices and controllable rare earth luminescent material.

利用超分子自组装构筑可控可逆智能材料已经成为当今材料科学、生命科学等领域的研究热点。然而，利用超分子非共价弱相互作用力构筑得到的材料质地较软，力学性能差，限制了其在某些特定领域的应用。在本项目中，我们拟将基于环糊精的超分子自组装与无机基质锂皂石相结合，设计并合成以锂皂石为框架基质，超分子非共价作用力为驱动力，兼具较高机械强度和可控可逆特性的有机-无机杂化水凝胶。另外，通过引入与环糊精尺寸匹配且具有光致异构特点的偶氮苯客体分子等手段，实现凝胶-溶胶过程的光控可逆调控。在此基础上，通过深入系统地研究该杂化宏观自组装过程的热力学参数和动力学参数，阐明该杂化宏观自组装过程的机理、模式、驱动力和影响因素等基础科学问题；研究所得水凝胶的机械性能和力学性能。该研究项目不仅具有非常重要的基础科学价值，同时还在生物填充材料、光响应探测器、可控稀土发光材料等领域具有重要的实际应用前景。

稀土配合物具有优异的发光性能（如量子效率高、荧光寿命长、单色性能好、发射光谱丰富），然而稀土配合物自身的缺陷如光、热稳定性差，易团聚、可加工性差等限制了其进一步器件化及从实验室向商业应用的大规模转化。将稀土配合物与无机基质相结合制备稀土有机-无机杂化材料成为解决这一问题的有效途径。在本项目中，我们利用多级杂化自组装的策略将稀土与锂皂石类纳米粘土相结合，制备了兼具良好机械强度和优异发光性能的杂化水凝胶。实验表明，多级自组装的策略不仅可以有效保持稀土配合物在水中的发光强度和量子效率；同时可有效避免物理掺杂体系中稀土离子分散不均匀、掺杂量低、易漏淅等缺陷，并赋予了凝胶可控可逆的特性。在此基础上通过引入光刺激响应性的主客体包合物实现了光控远程凝胶-溶胶可逆相转变；通过改变稀土离子的种类及比例实现了颜色可调杂化水凝胶的构筑。并深入系统地研究了杂化水凝胶的形成机理、模式、驱动力和影响因素等基础科学问题，这些数据可作为继续深入研究杂化宏观自组装的先导。该该研究项目不仅具有非常重要的基础科学价值，为之后的工作提供重要的理论依据和实验基础。同时，所制备的透明发光水凝胶及薄膜具有良好的光学性质、机械性能以及可加工性能，有望在激光、光学器件、太阳能电池等领域得到应用。