(63d) FRI/John G. Kunesh Award Lecture: in Search of New Paradigms for Crystal Engineering: Old Tricks, Novel Discoveries, and Future Challenges

Crystal engineering is a broad area of research that focuses on methods of designing and/or optimizing materials for diverse applications in fields spanning from energy to medicine. The ability to selectively control crystallization to achieve desired material properties requires detailed understandings of the thermodynamic and kinetic factors regulating crystal nucleation and growth. Combining this fundamental knowledge with innovative approaches to tailor crystal size, structure, and morphology can lead to the production of materials with superior properties beyond what is achievable by conventional routes. In this talk, I will discuss two mechanisms of crystal growth: (1) classical pathways involving 2-dimensional layer nucleation and advancement on crystal surfaces through monomer addition; and (2) nonclassical pathways, termed crystallization by particle attachment (CPA), involving the formation of metastable precursors that play a direct role in crystal nucleation and growth. Our group and collaborators have employed a combination of colloidal assays, surface science techniques, applied studies, and ab initio modeling to investigate crystallization in situ and elucidate the mechanisms of growth modification. To this end, we investigate modifiers that control crystallization in two distinctly different, yet fundamentally similar, areas of research. Here, I will discuss the progress we have made to develop modifiers as new drugs to prevent the formation of crystals in pathological diseases, such as kidney stones (calcium oxalate) and malaria (hematin). Our findings have spurred additional research thrusts, including the use of bio-inspired approaches to tailor the properties of commercial materials, such as zeolites, which are microporous aluminosilicates utilized in many separations processes. The adaptation of crystal growth modification to these materials poses many challenges, central among them being the complex mechanism(s) by which they grow. In this talk, I will discuss our ability to elucidate and control the growth of these materials; and summarize our recent efforts to develop commercially-viable methods of tailoring the physicochemical properties of crystals relevant to the separations industry.