Understanding complex ordered fluids: towards new materials for photonics and sensors

大多数人都听说过液晶--它们是用于笔记本电脑、移动的电话和一些最现代的电视机中的平板显示器的材料。这项技术是如此成功，以至于去年地球上的每个人都卖出了一台液晶显示器（LCD）。人们总是在推动更快、更好的显示设备。这些可能使用更低的功率，因此更环保，或者变得更复杂和更快，也许使它们成为专业的光电设备-改善电信和计算的东西。液晶不仅仅是高科技材料。它们是具有功能和秩序的流体，是许多生物系统的关键组成部分。例如，液晶帮助蜘蛛丝具有惊人的强度和柔韧性，它们在一些昆虫中产生美丽的颜色，甚至在你的大脑中发挥作用，而你的大脑应该是70%的液晶！该提案中的研究涉及技术前沿的新型液晶材料。我们希望研究的材料正在考虑用于一些新的应用，其中它们的光学特性或对表面的敏感性可能是有用的。我们可以进行一系列新的实验，包括散射非常精确能量的X射线（共振散射）和测量液晶散射光的微小变化（拉曼散射），这将使我们能够探测液晶系统中重要的确切顺序。我们还想建立一个实验，使我们能够挤压液晶，看看它们有多可压缩。我们相信，通过进行这一系列的实验，并仔细结合我们获得的所有信息，我们可以测试理论，并帮助理论家理解这种重要的物质状态是如何形成的。我们有新的材料，可以让我们做一些我们第一次提出的实验。此外，我们提出的实验的独特组合将使我们能够建立一个完整的图片，我们知道在这种液晶中形成的层是否在形成不同类型的液晶结构的过程中是重要的。了解这种特殊的液晶是如何有序排列的，其意义超出了技术。在学习物理学或材料科学时，我们试图理解为什么某些材料以它们的方式起作用，以便我们可以更好地利用它们的特性，或者化学家可以改进它们。液晶是物质的流体状态的一个例子，其中分子“自组装”，并且它们的方式非常微妙地取决于分子结构或成分的微小变化。这是如何发生的仍然没有很好的理解，尽管这个主题在纳米技术等领域变得越来越重要，其中具有功能的材料被组装成微小的结构，然后在更大的规模上发挥作用。自组装也是自然界中的一个重要过程，例如，组成我们的流体以一种可以发生非常高级功能的方式组装。我们计划的研究的一个重要方面是，我们希望了解我们系统中分子结构的微小变化如何导致其体积物理性质的巨大差异。这种研究具有非常广泛的相关性，因为它可能有助于我们了解自然界的运作方式。这最后一点也不仅仅是推测性的，我们最近利用我们对液晶光学的理解来建议一些鱼如何看到偏振光（不使用宝丽来太阳镜！）。毫无疑问，理解流体的自组装在许多科学领域都很重要。

Most people have heard of liquid crystals - they are the materials that are used in the flat-panel displays found in lap top computers, mobile phones and some of the most modern television sets. The technology is so successful that last year a liquid crystal display (LCD) was sold for every person on earth. There is always a push for faster, better display devices. These might use lower power, so are more environmentally friendly, or become more complex and faster, perhaps making them useful as specialist optoelectronic devices - things that improve telecommunications and computing. Liquid crystals aren't just high-tech materials though. They are fluids that have both function and order, and are a key component of many biological systems. For example liquid crystals help spider silk to have its amazing strength and flexibility, they cause the beautiful colours in some insects and even play a part in your brain which should be 70% liquid crystalline!The research in this proposal involves new liquid crystal materials at the forefront of technology. The materials we wish to study are being considered for use in a number of new applications where their optical properties or their sensitivity to surfaces might be useful. We can carry out a range of new experiments, including scattering x-rays of very precise energy (Resonant scattering) and measuring tiny changes in light scattered by the liquid crystal (Raman scattering), that will allow us to probe the exact kind of order that is important in our liquid crystal systems. We also want to build an experiment that will allow us to squeeze the liquid crystals to see how compressible they are. We believe that by carrying out this range of experiments and carefully combining all the information we gain, we can test theory and help theoreticians to understand how this important state of matter forms. We have new materials that will allow us to do some of the experiments we are proposing for the first time. Also, the unique combination of experiments that we are proposing will allow us to build a complete picture of whether the layers that we know form in this kind of liquid crystal are important in the process of forming the different types of liquid crystal structure. Understanding how this special kind of liquid crystal orders in the way it does has implications beyond technology. In studying physics or materials science, we try to understand why certain materials act in the way they do so that we can better use their properties, or so that chemists can improve them. Liquid crystals are an example of a fluid state of matter in which the molecules 'self-assemble' and the way in which they do depends very subtly on small changes in molecular structure or composition. How this happens is still not very well understood, despite this topic becoming increasingly important in areas like nanotechnology where materials with function are assembled into tiny structures that then act at a lager scale. Self-assembly is also a vital process in nature where, for example, the fluids we are composed of assemble in such a way that very high-level functions can take place. An important aspect of the research we plan is that we hope to understand how small changes in molecular structures in our systems lead to very large differences in their bulk physical properties. Such research has very broad relevance as it can potentially help us to understand how nature works. This final point isn't just speculative either / we recently used our understanding of liquid crystal optics to suggest how some fish see polarised light (without using Polaroid sunglasses!). There is no question that understanding self-assembly of fluids is important in many areas of science.