Materials World Network: Bioinspired Composite Single-Crystals - From Structural Evolution to Mechanical Characterization

Cornell University, Ithaca NY

Investigators

Abstract

TECHNICAL SUMMARY: With support from the Solid State and Materials Chemistry program and the Office of Special Programs in the Division of Materials Research, this research aims to develop a unified understanding of the formation, structure, and mechanical properties of synthetic and biologic single crystal composites. The Materials World Network team with members from Cornell University (supported by the Division for Materials Research), Lawrence Berkeley National Labs, and the UK (Universities of Leeds and Sheffield, supported by the EPSRC) offers a rare synergy of expertise in crystal growth, biomineralization, materials synthesis, polymer and colloid synthesis, mechanical properties, and materials characterization. Many natural systems produce elaborate composites in which fragile mineral single crystals and soft polymers are combined to create materials with superior mechanical properties. Such composites are typically understood and modeled in terms of homogeneous ideal mineral crystals embedded in a host organic matrix. However, the mineral single crystals are themselves composites in which a variety of organic and inorganic materials are occluded. Very little is known about how these single crystal composites form or their extraordinary properties. The research goals of this international collaboration are to: (1) Characterize single crystal biominerals and determine how their design leads to superior mechanical properties; (2) Translate these design strategies to the synthesis of calcite crystals occluding small molecules, structurally and chemically well-defined polymers and particles, and compliant and stiff frameworks, and evaluate the growth mechanisms involved; (3) Characterize and model the structural and mechanical properties of the composite crystals to elucidate synthesis-structure-function relationships; and (4) Begin to apply the understanding gained to generate novel composite materials. Just as the inspiration for this work comes from biological systems, the insights gained can be applied to better understanding the biological systems themselves. NON-TECHNICAL SUMMARY: With support from the Solid State and Materials Chemistry program and the Office of Special Programs in the Division of Materials Research, this collaboration brings together experienced and internationally-recognized researchers from the United States and Britain. The inspiration for this work comes from biominerals, which are formed using energy efficient, sustainable methods, and have unique morphologies and superior properties. Crystallization is a hugely important topic that has relevance to phenomena and applications as diverse as scaling, weathering, and the production of biomaterials, pharmaceuticals, and nanoparticles. Calcium carbonate, which is a significant focus of this proposal, is itself of tremendous industrial importance and an effective medium for carbon capture. By developing novel approaches to the synthesis of composite crystals, this research will provide a general and facile route for controlling the structure and properties of crystalline materials, leading to materials with tailored properties. This vision is anticipated to provide the basis for synthesizing next-generation materials such as artificial bone and tough synthetic dental enamel. In addition, the proposed project will promote intercultural exchanges in both training and teaching by offering: (1) Extended and short-term personnel exchanges of PIs and students with the UK collaborators; (2) International summer internships for undergraduates, with a focus on reaching under-represented minorities in STEM; and (3) a capstone international workshop on bio-inspired composite crystals organized by the PIs and their appointed researchers. The PIs will also work with science teachers to develop and distribute lesson plans for middle school students (Grades 6-8) with a focus on using examples from biomineralization to teach concepts of scientific classification and mechanical properties. In addition, this project will promote dialog and collaboration with national labs and facilities (e.g., the DOE-funded Molecular Foundry) to facilitate transfer of knowledge and capabilities for creation of useful technologies made possible by this research.