Cage-Enriched Macromolecules: Exploring New Dimensions in Materials Science

合成聚合物几乎存在于所有现代材料中，如塑料、树脂、涂料、弹性材料和复合材料，几乎存在于日常生活的各个方面。用于获得这种大分子的单体的结构通过控制它们如何折叠或包装在一起来决定所得到的聚合物的微观结构，这最终在宏观尺度上赋予材料不同的性能。聚合物传统上是由线形单体(如聚乙烯)和环状单体(如芳纶)制成的。后者比前者更僵化。这就转化为有价值的机械性能，如高机械强度。还可以设想第三种聚合物微结构，聚(笼)MERS，这是将三维笼子作为单体连接的结果。尽管在这一领域进行了几十年的努力，但到目前为止，只有两个家族的高相对分子质量聚(笼)MERS被制备出来，而且难度很大，效率很低：聚(螺旋桨烷)和聚金刚烷(聚金刚烷)。这主要是由于开发可行的合成方法来获得稳定的、可溶的/可加工的聚(CAGE)聚合物的困难。这项拟议的研究汇集了来自三个机构(Dalhousie、UQAM和UdeM)和两个省(魁北克和新斯科舍省)的三名高度积极的早期职业研究人员，以应对与获得这种基本有趣和具有实用潜力的先进聚合物材料相关的挑战。我们建议使用易于获取的磷-氮(PN)笼子作为一种媒介来探索材料科学中的新参数空间，并发现类似的碳基(有机)材料所不具备的新特性。由于笼子是刚性材料，将它们包含在聚合物链中可能会显示出更强的抗变形能力，并且由于笼子大多是空的，从它们派生的材料应该表现出低密度。因此，我们假设笼状致密材料将结合低密度和高刚性，使它们在运输、包装和航空航天工业中具有非常重要的应用价值。

Synthetic polymers are found in nearly all modern materials such as plastics, resins, coatings, elastics, and composites in nearly all aspects of daily life. The structure of monomers used to obtain such macromolecules dictates the microstructure of the resulting polymers by controlling how they can fold or pack together, which ultimately imparts different properties to materials at the macroscale. Polymers have traditionally been made from linear monomers, e.g. polyethylene, and ring-shaped-containing monomers, e.g. Kevlar. The latter are more rigid than the former. This translates into valuable mechanical properties such as their high mechanical strength. A third polymer microstructure, poly(cage)mers, can also be envisioned, being a result of connecting 3-dimensional cages as monomers. Despite several decades of efforts in this area, only two families of high-molecular weight poly(cage)mers have thus far been prepared and with great difficulty and poor efficiency: poly(propellane) and poly(adamantane). This is mainly due to difficulties in the development of viable synthetic methods to obtain stable and soluble/processable poly(cage)mers.This proposed research brings together three highly motivated early career researchers from three institutions (Dalhousie, UQAM, and UdeM) and two provinces (Quebec and Nova Scotia) to tackle challenges associated with accessing such fundamentally interesting and practically potentially advanced polymeric materials. We propose to use readily accessible phosphorus-nitrogen (PN) cages as a vehicle to explore new parameter space in materials science and discover emergent properties that are not available to analogous carbon-based (organic) materials. Since cages are rigid materials, containing them into a polymer chain might exhibit enhanced resistance to deformation, and since cages are mostly empty, materials derived from them should exhibit low density. Thus, we hypothesize that cage-dense materials will combine low density with high rigidity, making them very valuable for applications in the transportation, packaging, and aero-space industry.