New ideas and new materials in polymer science

这项提议旨在解决软凝聚态物理学中一些最困难的悬而未决的问题。许多软固体是玻璃状的(无定形固体)。玻璃可以被认为是最常见的固体，就像足够快的冷却一样，即使是通常采用晶体结构的材料也可以形成玻璃。尽管它们很重要，无论是作为技术上重要的材料，还是作为凝聚态物质最常见的形式之一，我们对玻璃的形成缺乏深入的理论理解。玻璃的实验研究面临的挑战之一是与玻璃材料相关的非常长的弛豫时间，因为这会导致材料本身失去平衡，并继续老化(随时间变化)无限期。最近发现的稳定玻璃-那些模仿了数千年甚至数百万年老化的玻璃-是我们寻找近平衡玻璃系统进行研究的理想候选者。我们将继续探索通过制造和研究第一个由聚合物制成的稳定玻璃来发展对玻璃和玻璃形成的理解。我们将把这一点与我们的理论努力结合起来，旨在提供一个更简单的框架来理解玻璃材料的大部分物理原理。除了我们对玻璃固体的研究外，我们还将探索聚合物中结晶度的各个方面。许多聚合物是部分结晶的，我们将研究高度单分散的小分子聚合物，以加深我们对聚合物中晶体形成的理解。众所周知，聚合物表现出各种形式的自组装，其中一种形式是一种物种在表面的分离。链端的情况特别有趣，因为偏析的驱动力是纯粹的熵。链端偏析的驱动力很弱，给研究带来了很大的挑战。我们将对不同相对分子质量的聚合物共混物中表面离析的存在和程度提供明确的答案，从而提供链端离析的实验验证。所有的实验项目都将使用我们的直接物理气相沉积聚合物的新技术。这项技术允许以前所未有的单色性和大量分离小聚合物分子(由~10个单体单元组成)。我们的新技术还能够重新定义如何将固体聚合物沉积到衬底上，并开辟了软纳米技术的新途径。总体而言，该提议对我们对软凝聚物质的基本理解和这些材料的技术应用都有很大的影响。

This proposal aims to tackle some of the most difficult outstanding problems in soft condensed matter physics. Many soft solids are glassy (amorphous solids). Glasses could be argued to be the most common solids, as with sufficiently rapid cooling, even materials that usually adopt a crystalline structure can be made to form a glass. Despite their importance, both as technilogically important materials, and as one of the most common forms of condensed matter, we lack a deep theoretical understanding of the formation of glasses. One of the challenges that face the experimental study of glasses is the very long relaxation times associated with glassy materials, as this results in materials that are inherently out of equilibrium, and continue to age (change over time) for indefinite time periods. The recent discovery of stable glasses - those which mimic glasses that have aged for thousands over even millions of years- are ideal candidates as we look for near equilibrium glassy systems to study. We will continue on our quest to develop an understanding of glasses and glass formation by making and studying the first stable glasses made from polymers. We will couple this with our theoretical efforts that aim to provide a more simple framework to understand much of the physics of glassy materials. In addition to our study of glassy solids, we will also explore aspects of crystallinity in polymers as well. Many polymers are partially crystalline, and we will study highly monodisperse small polymers in order to deepen our understanding of crystal formation in polymers. Polymers are known to exhibit various forms of self assembly, and one form of this is segregation of one species to the surface. The case of chain ends is particularly interesting as the driving force for segregation is purely entropic. The weak driving force from chain end segregation makes it very challenging to study. We will provide a definitive answer to the existence and extent of surface segregation in blends of polymer with different values of molecular weight, and thus provide experimental verification of chain end segregation. All of the experimental projects will utilize our new technique of direct physical vapour deposition of polymers. This technique allows for the isolation of small polymer molecules ( comprised of <~ 10 monomer units) with unprecedented monodsipersity and in bulk quantities. Our new technique also has the ability to redefine how solid polymers can be deposited onto a substrate, and opens up new avenues in soft nanotechnology. Overall, the proposal has great promise for impact in both our fundamental understanding of soft condensed matter and the technological applications of these materials.