The structure of water in halloysite nanotubes

Water is important in many scientific and technological areas, yet our understanding of this remarkable liquid remains very incomplete. In may cases, it is the properties of water at a surface or interface, rather than in the bulk, that are the key to the system's overall behaviour. There are many diverse examples where this is the case, ranging from protein folding to the uptake of water by soils. In this experiment, we will use the unique powers of neutron scattering to measure the structure of water in a particular type of clay mineral, known as halloysite. Halloysite is remarkable in this context, because it occurs as nano-scale tubes, which are formed from rolled-up scrolls of the clay sheets (like a swiss-roll, where a single molecular layer of water is the jam, and the clay sheet is the sponge-cake). Our expeirments will allow us to study water structure under extreme confinement.

水在众多科技领域中均具有重要价值，但我们对这种非凡液体的认知仍十分有限。在多数情形下，决定体系整体行为的并非水的本体性质，而是其在表面或界面处的特性。此类应用场景不胜枚举，从蛋白质折叠到土壤持水过程，均属此列。本实验将利用中子散射（neutron scattering）的独特优势，对一种名为埃洛石（halloysite）的黏土矿物中的水结构进行测量。埃洛石在此研究语境中极具特殊性：它以纳米尺度管状结构存在，由黏土片层卷曲而成（如同瑞士卷：单分子层水即为夹心层，黏土片层则为蛋糕胚）。本实验将助力我们研究极端限域环境下的水结构。