CAREER: Harnessing Molecular Interactions and Multi-Bioinspired Toughening in Inorganic Minerals for Next-Generation Binders

This Faculty Early Career Development (CAREER) award will support research that looks to derive a fundamental understanding of molecular interactions and toughening mechanisms in inorganic minerals for tailoring tough and durable structural materials. A key innovation is anticipate to lie in turning ubiquitous calcium carbonate into a monolithic binder as a potential alternative to cement and concrete, rather than a raw material thermally decomposed in traditional cement manufacturing. Towards this end, novel synthesis and strengthening pathways will be explored to address the fundamental challenges in constructing continuously structured inorganic monoliths and tackling the poor fracture toughness and low tensile strength of crystalline minerals. By redefining the synthesis process and improving the properties of materials and structures in a truly sustainable and cost-effective way, the anticipated project outcomes could ultimately shed light on multiple research areas and industrial sectors, including civil engineering, materials science, mechanical engineering, advanced manufacturing, and the utilization of abundant and renewable resources with long-term economic and environmental benefits. The research efforts will be integrated with educational activities, including the BRIGHT (Build Resilient, Innovative, and Green Homes on Terra), Science Playground, and SEED (Sustainability Exploration, Engagement, and Discovery) programs, to offer interactive, hands-on learning experiences for future engineers and scientists. The principal hypothesis of this research is that inorganic carbonate minerals can be turned into polymerizable phases capable of forming monolithic binders if stable clusters with controlled sizes can be tailored and regulated to trigger non-classical nucleation and crystallization. This hypothesis will be tested by computationally and experimentally investigating polymer-like precursors, refining reaction pathways, and regulating molecular-scale interactions. Inspired by the mineralization pathways in living organisms, the unique non-classical strategy looks to provide a thermodynamically favored pathway for tailoring mineral-based binders under ambient conditions by bypassing the critical free energy that must be overcome in conventional approaches. To enhance toughness and tensile strength, multiple bio-inspired toughening mechanisms, including copolymerization with organic monomers to tailor hybrid molecules, incorporation of coherent nanodomains to trigger pre-strained crystal lattices, and construction of packed and aligned nano-reinforcement, will be tailored and integrated across multiple length and time scales. The fundamental knowledge and insights gained from this project look to advance the reimagining of structural materials design by unlocking a pathway that is prevalent in nature yet rarely replicated through artificial synthesis, offering transformative material solutions for future civil infrastructure. 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.