Hierarchical composites by gluing of nano- and mesocrystals

通过粘合纳米晶体和介晶形成分层复合材料

• 批准号: 126361268
• 负责人: Professor Dr. Helmut Cölfen (†)
• 金额: --
• 依托单位: Arbeitsgruppe Physikalische Chemie (AG Cölfen)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/126361268?language=en
• 关键词: Hierarchical; composites; gluing; nano; mesocrystals

In natural organic inorganic composites such as bone or nacre, stiff and very brittle mineral crystals are joined by soft organic materials. Due to a sophisticated hierarchical structuring and a well controlled coupling at the interface between the two components, these biological structures combine both stiffness and toughness. By means of arranging inorganic crystals with the help of organic molecules, natural biocomposites also achieve remarkable optical and magnetic properties. Inspired by these concepts, we manufacture biomimetic composite structures by gluing together mineral particles with polymers and hierarchical structuring by one step self organization via liquid crystal formation.The polymers used are copolymers with cholesteryl LC side chains or helical backbones carrying amino acid (carboxyl/amino) gluing units (various LC/gluing unit ratios and chain lengths). The polymers form chiral nematic lyotropic phases on the µm length scale, and the carboxyl groups of the polymer side chains act as gluing units by binding to the nanoparticle faces via Coulomb interaction or hydrogen bonding. Two hierarchical level composite bulk samples with anisotropic nanocrystals (Laponite clay platelets and vanadium pentoxide nanoparticles) and LC polymer are produced via one step self organization: alignment of nanoparticles (first level) within a structured organic matrix (second level). Different analytical techniques (light microscopy, micro tomography, SEM, SAXS, and TEM) revealed the hierarchical structuring of Laponite and vanadium pentoxide composite materials from the mm and µm lengthscale to the nm lengthscale. Mechanical characterization by nanoindentation supported the observed structural anisotropy.This approach allows for systematic variation of structures and for optimizing the mechanical performance as well as investigating the effects of the hierarchical structuring on the mechanical properties (structure property relationship). In addition, our objective is the fabrication of multifunctional composite materials with optimized mechanical as well as optical/magnetic properties, finally aiming at investigating the influence of the hierarchical structuring on the final material properties. To this end, hierarchically structured composite materials with other technologically relevant and abundant materials like gold nanorods and magnetic nanoparticles will be synthesized by applying our structuration concepts. Furthermore, by using magnetic nanoparticles, the nanoparticle alignment can be optimized by means of an external magnetic field, potentially enabling nanoparticle orientation up to the macroscopic scale.

在天然有机无机复合材料中，如骨或珍珠层，坚硬且非常脆的矿物晶体由柔软的有机材料连接。由于两个组件之间的界面处的复杂的分层结构和良好控制的耦合，这些生物结构联合收割机刚度和韧性。天然生物复合材料通过有机分子对无机晶体的有序排列，也获得了显著的光学和磁学性质。受这些概念的启发，我们通过将矿物颗粒与聚合物粘合在一起并通过液晶形成一步自组织分层结构来制造仿生复合结构。所使用的聚合物是具有胆固醇LC侧链或螺旋主链的共聚物，其携带氨基酸（羧基/氨基）粘合单元（各种LC/粘合单元比率和链长度）。聚合物在微米长度尺度上形成手性溶致相，并且聚合物侧链的羧基通过库仑相互作用或氢键结合到纳米颗粒表面而充当胶合单元。通过一步自组织产生具有各向异性纳米晶体（Laponite粘土片晶和五氧化二钒纳米颗粒）和LC聚合物的两个分级水平复合体样品：纳米颗粒（第一水平）在结构化有机基质（第二水平）内的对准。不同的分析技术（光学显微镜、显微断层扫描、SEM、SAXS和TEM）揭示了Laponite和五氧化二钒复合材料从mm和µm长度尺度到nm长度尺度的分级结构。纳米压痕力学表征支持所观察到的结构各向异性，这种方法允许系统的变化的结构和优化的机械性能，以及调查的分层结构的机械性能（结构性能关系）的影响。此外，我们的目标是制造具有优化的机械性能以及光学/磁性的多功能复合材料，最后旨在研究分层结构对最终材料性能的影响。为此，通过应用我们的结构化概念，将合成具有其他技术相关和丰富材料（如金纳米棒和磁性纳米颗粒）的分层结构复合材料。此外，通过使用磁性纳米颗粒，可以通过外部磁场优化纳米颗粒的排列，从而可能使纳米颗粒取向达到宏观尺度。