Biomimetic Routes to Crystals with Superior Mechanical Properties

大自然能够显著地控制矿物的生长，产生骨、牙齿和贝壳等生物矿物，这些矿物经常显示出不同寻常的形态和优越的机械性能。显然，这是在温和的条件下实现的，并为新材料的设计和合成提供了独特的灵感。生物矿物是一种典型的复合材料，由少量的有机物质与矿物成分组成，正是这种物质及其结构组织导致了优异的机械性能。许多生物矿物要么是无定形的，要么是多晶的，因此很容易解释为什么这些结构具有良好的机械性能。然而，特别值得注意的是生物单晶，它也可以表现出相当大的抗裂性，这种行为通常被认为是来自晶体中被遮挡的有机大分子。这与合成单晶不同，合成单晶通常由于存在低能量的断裂面而非常容易断裂。这项建议将研究在晶体中加入添加剂作为提高其机械性能的途径，目的是生产具有更好的抗断性的各种晶体，并了解如何在单晶中加入这些添加剂。虽然有机添加剂的加入非常适合在环境条件下形成和使用的生物矿物，但它不能应用于在合成和使用过程中通常暴露在更极端条件下的先进材料。该项目为这一问题提供了一种新的解决方案，并将首次在单晶中加入化学和热稳定的颗粒，以改善其机械性能。这些复合晶体的机械性能将与含有有机添加剂的合成晶体和单晶生物矿物进行比较。该项目还将提供对这一生物起源战略的第一次系统和定量研究。

Nature is capable of remarkable control over mineral growth, producing biominerals such as bones, teeth and seashells which frequently display unusual morphologies and superior mechanical properties. Clearly this is achieved under mild conditions, and provides a unique inspiration for design and synthesis of new materials. Biominerals are typically composite materials, comprising a small amount of organic material in association with the mineral component, and it is this together with their structural organisation that results in the superior mechanical properties. Many biominerals are either amorphous or polycrystalline, and it is relatively easy to explain why these structures have good mechanical properties. Particularly remarkable, however, are biogenic single crystals which can also show considerable fracture resistance, behaviour which is generally considered to derive from organic macromolecules occluded within the crystals. This is in contrast to synthetic single crystals which typically fracture very easily due to the presence of low-energy fracture planes.This proposal will investigate incorporation of additives within crystals as a route to enhancing their mechanical properties, with the aim of producing a wide range of crystals with improved fracture resistance, and understanding how such additives can be incorporated within a single crystal. Although incorporation of organic additives is well-suited to biominerals which are formed and used under ambient conditions, it cannot be applied to advanced materials which are typically exposed to more extreme conditions during synthesis and use. This project offers a novel solution to this problem, and will for the first time incorporate chemically and thermally stable particles within single crystals to improve their mechanical properties. The mechanical properties of these composite crystals will be compared with both synthetic crystals incorporating organic additives and single crystal biominerals. The project will also provide the first systematic and quantitative study of this biogenic strategy.