Understanding the effects of confinement on near-surface soft nanostructures using neutron and X-ray reflection

表面的性质可以通过用聚合物和表面活性剂涂覆来广泛地改变。从煎锅上的特氟隆涂层到我们在海滩上涂的防晒霜，这样的例子比比皆是。聚合物在表面的另一个熟悉的方面是在发动机中的润滑，如果没有它的保护涂层，发动机就会卡住。我们通过这些改性生产的新表面可以根据所使用的涂层制成强粘性、不粘、生物活性、抗菌等，并且可以针对每个应用进行定制。在工业过程中，颜料、漆基和药物等颗粒经常被分子包覆，以控制其加工或最终用户特性。虽然小分子如肥皂和洗涤剂在这些表面上的行为已经被很好地理解，但大分子如聚合物的作用还不清楚，特别是当与表面活性剂和纳米颗粒相互作用时。当两个涂层表面接触时（比如当血细胞粘附在过滤膜上或当两滴墨水聚在一起时），界面上发生了什么还不清楚。在这些有限空间中形成的分子结构中的实际层间力尚未详细研究，因为进行这种实验测量非常困难。深入了解这些结构将有助于我们详细了解这些系统中的聚合物行为。有了这些知识，就有可能设计出满足这些功能的新型材料，而不是依赖于偶然的发现;这样，环境影响或成本等因素就可以得到更大的重视，而不是将选择限制在已知的少数几种材料上。了解这些液体与固体表面的相互作用将有助于提高开关速度和功耗，这将有助于开发新的显示技术，如反射，电子paper.We正在构建一个压缩设备，其中一个灵活的膜被推到一个非常平坦的10厘米直径的石英块。这两个表面结合在一起模拟了两个小颗粒结合在一起（例如我们前面提到的细胞和膜或两个墨水滴），但是在更大的尺度上，这样我们就可以看到它们之间的溶液中发生了什么。在我们压缩表面的同时，我们将通过界面照射中子或X射线束，以测量差距中的结构。中子在某些方面与X射线相似，因为它们可以测量亚纳米精度的结构，并且可以穿过许多材料，使我们能够看到内部。位于牛津郡ISIS设施的新的第二目标站是将进行这些实验的地方之一。我们预计，与有助于稳定颗粒（例如用于药物输送）的聚合物相比，导致颗粒絮凝（例如用于废水处理）的聚合物将具有非常不同的结构。详细了解这些结构将有助于我们详细了解聚合物中观察到的各种现象，包括润滑，稳定和絮凝。

The properties of surfaces can be modified extensively by coating them with polymers and surfactants. Examples of this are abundant from the Teflon coating on a frying pan to the sunscreen we wear at the beach. Another familiar aspect of polymers at surfaces is lubrication in an engine that would seize up without its protective coating. The new surfaces we produce through these modifications can, for example, be made strongly adhesive, non-stick, biologically active, anti-bacterial, depending on the coatings used and these can be tailored for each application. In industrial processes, particles such as pigments, paint bases and pharmaceuticals are frequently coated with molecules to control either their processing or end-user properties. While the behaviour of small molecules such as soaps and detergents at these surfaces is well understood, the role of larger molecules such as polymers is not, especially when interacting with surfactants and nanoparticles.When two coated surfaces come together (say when a blood cell adheres to a filtration membrane or when two drops of ink coalesce), what happens at the interface is quite unclear. The actual interlayer forces in the molecular structures that form in these confined spaces have not been studied in detail because making such experimental measurements is very difficult. Understanding these structures in depth will help us develop a detailed picture of polymeric behaviour in these systems. With this knowledge, it should become possible to design novel materials to fulfil these functions rather than rely on serendipity; factors such as environmental impact or cost can then be given greater weight rather than restricting choice to the few materials that are known to work.We also intend to look at advanced uses of structured liquids such as those used in liquid crystal displays. Understanding the interactions of these liquids with solid surfaces will assist in improving switching speed and power consumption which will assist the development of new display technology such as reflective, electronic paper.We are constructing a compression device where a flexible membrane is pushed against a very flat 10cm diameter quartz block. These two surfaces coming together mimic two small particles coming together (such as the cell and membrane or two ink drops we mentioned earlier) but at a larger scale so that we can see what is happening in the solution between them. At the same time that we compress surfaces, we will shine a neutron or X-ray beam through the interfaces to measure the structures in the gap. Neutrons are similar in some respects to X-rays in that they can measure structures with sub-nanometre precision and can pass through many materials allowing us to see inside. The new 2nd Target Station at the ISIS facility in Oxfordshire is one of the places where these experiments will be undertaken.We expect that a polymer that causes flocculation of particles (e.g. for waste water treatment) will have a very different structure compared with a polymer that helps stabilise particles (e.g. for drug delivery). Understanding these structures in detail will help us develop a detailed picture of various phenomena that are observed with polymers including lubrication, stabilisation and flocculation.