基于预设计框架诱导组装生长法的仿珍珠层块体结构材料制备及性能研究

The incorporation of biological hierarchical structures, such as the brick-and-mortar structure in nacre, into artificial structural materials is a promising strategy for developing future structural materials with superior properties. However, the fabrication of nacre-inspired bulk structural materials is retarded by low efficiency, inevitable incompatibility and insufficient control of the fine structures. In order to address these challenges, the applicant demonstrated previously that bulk synthetic nacre can be feasibly produced by a predesigned matrix-directed mineralization process, where the fine structures of the material have been successfully controlled. Herein, based on our assembly-and-growth strategy, we proposed a new research project to systematically solve the above problems. This roadmap for fabricating nacre-inspired bulk materials is composed of three steps: 1) Matrixes with predesigned micro structures are produced via freeze-casting or programmable 3D printing technique; 2) Different precursor solutions are pumped through the matrixes to accordingly ensure the precipitation and growth of hydroxyapatite, aluminum hydroxide and metal organic frameworks in the matrixes; 3) The obtained matrixes are further treated with proper after-treatments, resulting in the final bulk materials. In our plan, the control of the multiscale hierarchical structure and the fine structures can be achieved via adjusting the structures of the matrixes and the reaction conditions. Subsequently, the relationship between the hierarchical structure of the materials and their performances can be analyzed. By implementing this project, a systemic and universal strategy for the fabrication of nacre-inspired bulk structural materials will be established, which provides a strong toolkit for designing and making better artificial materials and significantly promotes the exploitation of structural materials with extraordinary performance.

在人工结构材料中，引入以珍珠层结构为代表的微纳多级结构将为研发具备更佳性能的未来结构材料提供一条可靠途径。然而，仿珍珠层块体结构材料的制备仍面临效率低、材料局限、精细结构难调控等问题。申请人在前期工作中提出以具有预设计微观结构的框架诱导矿化生长的方法快速制备仿珍珠层块体材料，并在该体系中实现了精细结构调控。本项目拟以此方法为基础，首先通过取向冻结及3D打印等技术构筑具有预设计结构的框架，再在框架中通入前驱体溶液分别使磷酸钙、氢氧化铝和金属有机框架等材料在框架内沉积，最后经后处理得到仿珍珠层块体材料；拟通过调节框架结构和沉积条件实现对跨尺度多级结构及其他精细结构的调控，并研究结构与材料性能的关系。通过本项目的实施，可建立一套系统而普适的仿珍珠层块体结构材料制备方法，进一步促进仿生结构材料制备技术的发展，为研制高性能结构材料提供技术支撑。

在人工结构材料中引入以珍珠层结构为代表的微纳多级结构将为研发具备更佳性能的未来结构材料提供一条可靠途径。然而制备具有仿生微纳结构的材料仍是一项重大挑战，即难以兼顾材料制备的精度和效率。本项目采用了模拟生物结构材料生长方式的框架诱导生长法，制造出不同组分的、不同功能的具有复杂多级结构的仿生结构材料。通过调节框架结构和沉积条件实现对跨尺度多级结构及其他精细结构的调控，并研究结构与材料性能的关系。同时，本项目基于材料生长法的独特优势，在纳米尺度上实现了材料性能的优化。通过本项目，初步建立了一套普适的仿珍珠层块体结构材料制备方案。.本项目主要开展了三项研究。在磷酸钙基仿生复合材料的制备与骨修复应用研究中，制备了具有仿生结构的磷酸钙/几丁质复合材料。所使用的几丁质在湿润状态不溶胀、不溶解，不会在体内环境中出现性能剧烈下降或解体，作为骨植体引发的炎症反应较轻；同时控制矿化反应条件，制备了具有不同晶型和降解速度的磷酸钙。在仿生MOFs/聚合物块体复合材料的制备与分离性能研究中，筛选了若干种聚合物，发现丝蛋白对前驱体有较好的吸附作用，能够在框架上生长一层完整的MOFs。实验结果表明其具有较好的气体分离效果。在残余应力增韧的仿珍珠层结构材料机理研究中，通过纳米颗粒与基体晶格之间有较强的相互作用并产生了残余应力，最终显著提升了材料的断裂韧性。与其纯无机材料相比，断裂韧性提高到16倍。