Dense Extended Hydrocarbon Framework Materials (3D Polymers)

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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.