The Effects of Polydispersity on Self Assembly in Block Copolymers.

众所周知，制造业对聚合物分子构成的塑料材料有着巨大的依赖。一种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制成的。正如人们所预料的那样，一块塑料中的单个分子长度不同。事实上，这种链长度的多分散性在商业材料中是非常大的，这是合成分子的简单而经济的方法的结果。幸运的是，事实证明，当聚合物成型或加工成各种产品时，高度的多分散性实际上是有利的。现在有一些潜在的应用涉及新一代更复杂的聚合物，称为双嵌段共聚物，其中链的第一部分（即嵌段）由一种类型的单体形成，第二个嵌段由另一种类型的单体形成。化学上不同的嵌段分离的一般趋势导致共聚物在材料内的自组织，从而产生独特的性能和行为。为了研究目的，科学家们已经做出了很大的努力来生产模型材料，其中的多分散度非常低。虽然这在试图了解其复杂行为时提供了巨大的优势，但合成单分散二嵌段共聚物的成本是潜在商业应用的严重障碍。当前项目的目的是了解多分散性的引入如何影响双嵌段共聚物材料的行为。这将涉及实施新的合成方法来生产具有良好表征链长分布的多分散二嵌段共聚物，并结合广泛的实验技术来探测分子的自组织。然后将实验观测结果与最先进的理论预测进行比较。希望是，在简单的聚合材料的情况下，多分散性不仅降低了生产成本，而且提供了有利的性能。

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.