New ideas and new materials in polymer science

高分子科学新思想、新材料

• 批准号: RGPIN-2017-05192
• 负责人: Forrest, James
• 金额: $ 2.62万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=650951
• 关键词: New; ideas; new; materials; polymer

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.

该建议旨在解决软凝结物理学中一些最困难的问题。 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，就像有足够快速的冷却一样，甚至通常采用晶体结构的材料也可以形成玻璃。尽管它们的重要性是技术上重要的材料，也是凝结物质的最常见形式之一，我们对玻璃的形成缺乏深刻的理论理解。面对眼镜实验研究的挑战之一是与玻璃材料相关的很长的松弛时间，因为这会导致材料本质地超出平衡状态，并且在不定时间的时间段内继续老化（随时间变化）。最近发现的稳定眼镜 - 那些模仿数百万年龄在数百万年内陈化的眼镜的玻璃杯是理想的候选者，因为我们寻找近乎平衡的玻璃系统进行研究。我们将继续寻求通过制造和研究由聚合物制成的第一批稳定眼镜来发展对眼镜和玻璃形成的理解。我们将将其与理论上的努力相结合，旨在提供一个更简单的框架，以了解许多玻璃材料的物理学。除了研究玻璃固体外，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聚合物，以加深我们对聚合物晶体形成的理解。已知聚合物表现出各种形式的自组装，其中一种形式是将一种物种隔离到表面。链端的情况特别有趣，因为隔离的驱动力纯粹是熵。链端隔离的较弱的驱动力使研究变得非常具有挑战性。 我们将对具有不同分子量值的聚合物混合物中表面分离的存在和程度提供明确的答案，从而提供了链端隔离的实验验证。所有实验项目都将利用我们的新技术直接物理蒸气沉积聚合物。该技术允许将小聚合物分子（由<〜10个单体单元组成）分离，具有前所未有的单剂量和大量。 我们的新技术还可以重新定义如何将固体聚合物沉积到底物上，并打开软纳米技术方面的新途径。总体而言，该提案对我们对软凝结物质的基本理解和这些材料的技术应用有很大的影响。