Dense Extended Hydrocarbon Framework Materials (3D Polymers)

由简单碳氢化合物构成的聚合物固体主要以一维（1D）链形式存在，较少以石墨烯等二维聚合物形式存在。虽然针对3D烃聚合物的研究已经产生了低密度的共价有机和金属有机框架，但尚未合成出具有高强度和高化学能密度的致密3D烃框架聚合物。这些扩展的固体，当由低Z元素制成时，本质上是硬而轻的，例如金刚石和c-BN，并且通常表现出优异的热、机械、化学和光电性能，构成了一类新的新材料。该项目由材料研究部固态和材料化学项目支持，华盛顿州立大学（WSU）的Choong-Shik Yoo教授和他的研究小组将研究第一排和第二排元素固体的密集固体混合物的压力诱导转化，旨在开发适合环境条件稳定的密集扩展框架材料（EFM）。这项研究将通过在华盛顿州立大学、大型科学用户设施（APS、LCLS、XFEL）和美国能源部国家实验室（LLNL、LANL、SNL）进行尖端实验技术的重要实践经验，为研究生、本科生和博士后研究人员提供特殊的教育和培训机会。该项目的多学科性质也为学生提供了跨多个学科工作的独特经验，通常是在大规模的高知名度研究中，并有充足的合作机会。密集的框架结构在高压下无处不在，但通常在可怕的高压下形成，在释放压力时变得不稳定。因此，只有少数系统在环境条件下被回收，这限制了材料在基础科学发现领域的发展，并倡导了一个令人兴奋的新研究领域，以了解并最终控制低Z扩展固体的稳定性、键合、结构和性能。该项目由材料研究部固态和材料化学项目支持，将使用大压缩、致密固体混合物和动力学控制过程来控制主要由共价C/H/N/O单键制成的扩展框架材料（EFM）的结构、键合和稳定性。拟议的研究工作将集中在压力下三种特定的固态化学反应上：(A)共聚到化学计量高强度EFM；(B)氧化还原化学到非化学计量的间隙填充的多功能EFM；(C)低维碳和BN包封纳米级EFM的界面化学。通过科学发现和创新材料的发展，提出的研究将利用各种形式的EFM的结构-性能-功能关系，阐明控制致密固态化学的基本原理，并展示多功能EFM在极端机械，热和化学条件下可持续发展的革命性能力。所提出的研究策略涉及应用固态材料化学、凝聚态物理、物理化学、材料科学和工程等广泛的互补科学方法，从而实现远远超出本提案主题的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARYPolymeric solids made of simple hydrocarbons are primarily in one-dimensional (1D) chains and less frequently in 2D polymers like graphene. While research efforts aimed at the development of 3D hydrocarbon polymers have resulted in low-density covalent-organic and metal-organic frameworks, the synthesis of dense 3D hydrocarbon framework polymers with high strength and high chemical energy density has not been achieved. These extended solids, when made of low Z elements, are intrinsically hard yet light, e.g., diamond and c-BN, and often exhibit superior thermal, mechanical, chemical, and electro-optical properties and constitute a new class of novel materials. With this project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, Professor Choong-Shik Yoo and his research group at Washington State University (WSU) will investigate pressure-induced transformations of dense solid mixtures of first- and second-row elemental solids, aimed at development of dense extended framework materials (EFM) amenable to the stabilization at ambient conditions. This research will provide exceptional education and training opportunities for graduate and undergraduate students and postdoctoral researchers through significant hands-on experience in cutting-edge experimental technologies at WSU, large-science user facilities (APS, LCLS, XFEL), and DOE national laboratories (LLNL, LANL, SNL). The multidisciplinary nature of this project also provides students unique experience in working across many academic disciplines, often on large-scale high-profile research, with ample opportunities of enabling collaborations.TECHNICAL SUMMARYDense framework structures are ubiquitous at high pressures, but often formed at formidably high pressures and become unstable upon releasing the pressure. As a result, only a few systems have been recovered at ambient conditions, limiting the materials at the realm of fundamental scientific discovery and advocating an exciting new research area to understand and, ultimately, control the stability, bonding, structure, and properties of low Z extended solids. This project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, will use large compression, dense solid mixtures, and kinetic controlled processes to control the structure, bonding and stability of extended framework materials (EFM) made primarily of covalent C/H/N/O single bonds. The proposed research efforts will be focused on three-specific solid-state chemical reactions under pressures: (A) Copolymerization to stoichiometric high-strength EFM; (B) Redox chemistry to nonstoichiometric interstitial-filled multifunctional EFM; and (C) Interface chemistry to nm-scale EFM encapsulated in low-dimensional carbon and BN. Through scientific discoveries and innovative materials developments, the proposed research will exploit the structure-property-functional relationships of various forms of EFM, elucidate the basic principles governing dense solid-state chemistries, and demonstrate the revolutionary capabilities of multifunctional EFM sustainable to extreme mechanical, thermal and chemical conditions. The proposed research strategy involves application of a broad range of complimentary scientific approaches from solid-state materials chemistry, condensed matter physics, physical chemistry, materials science and engineering, thus achieving the impact well beyond the subject matter of this proposal.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.