The Effects of Polydispersity on Self Assembly in Block Copolymers.

众所周知，制造业对由聚合物分子组成的塑料材料有着巨大的依赖。典型的现成聚合物是通过将大量(例如，数千个)化学上相同的单元(称为单体)连接在一起形成长链分子而产生的。正如人们可能预料的那样，一块塑料中的各个分子的长度不同。事实上，这种链长的多分散性在商业材料中非常大，这是由于合成分子的方法简单但成本效益高。幸运的是，事实证明，高度的多分散性在将聚合物成型或加工成各种产品时是有利的。现在出现了一些潜在的应用，涉及称为两嵌段共聚物的新一代更精细的聚合物，其中链的第一部分(即嵌段)由一种类型的单体形成，第二嵌段由另一种类型的单体形成。化学上不同的嵌段分离的总趋势是材料中的共聚物自组织，从而产生独特的性能和行为。为了研究目的，科学家们努力制作多分散度很低的模型材料。虽然这在试图了解它们的复杂行为时提供了巨大的优势，但合成单分散两嵌段共聚物的成本严重阻碍了潜在的商业应用。本项目的目的是了解多分散性的引入如何影响两嵌段共聚物材料的行为。这将涉及到新的合成方法的实施，以生产具有良好特征的链长分布的多分散两嵌段共聚物，并结合广泛的实验技术来探索分子的自组织。然后将实验观察结果与最先进的理论预测进行比较。人们希望，就像简单的聚合物材料一样，多分散性不仅可以降低生产成本，还可以提供有利的性能。

As everyone is well aware, the manufacturing sector has a huge reliance on plastic materials composed of polymeric molecules. A typical off-the-shelf polymer is created by linking together a large number (e.g., thousands) of chemically-identical units (called monomers) to form long-chain molecules. As one might expect, the individual molecules within a piece of plastic differ in length. In fact, this polydispersity of chain lengths is extremely large in commercial materials, as a consequence of the simple but cost-effective methods of synthesising the molecules. Fortunately, it turns out that a high-degree of polydispersity is, in fact, advantageous when shaping or processing the polymers into various products.There are now emerging potential applications involving a new generation of more elaborate polymers called diblock copolymers, where the first part of the chain (i.e., block) is formed from one type of monomer and the second block is created from another type of monomer. The general tendency for the chemically-distinct blocks to separate causes self-organisation of the copolymers within the material, resulting in unique properties and behaviour. For research purposes, scientists have made great efforts to produce model materials, where the degree of polydispersity is very low. Although this provides a huge advantage when trying to understand their complicated behaviour, the cost of synthesising monodisperse diblock copolymers is a serious impediment to potential commercial applications. The aim of the current project is to understand how the introduction of polydispersity affects the behaviour of diblock-copolymer materials. This will involve the implementation of novel synthetic methods for producing polydisperse diblock copolymers with well-characterised chain-length distributions combined with a wide-range of experimental techniques for probing the self-organisation of the molecules. The experimental observations will then be compared with state-of-the-art theoretical predictions. The hope is, as in the case of simple polymeric materials, that polydispersity not only reduces production costs but also provides advantageous properties.