(468b) New Paradigms in Crystal Engineering: Tailoring the Physicochemical Properties of Materials for Chemical and Biomedical Applications

Crystal engineering is a broad area of research that focuses on methods of designing and/or optimizing materials for diverse applications in fields spanning energy to medicine. The ability to selectively control crystallization to achieve desired physicochemical 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 has the capability to produce materials with superior properties. In this talk, I will discuss materials that grow by two disparate mechanisms: classical pathways involving 2-dimensional layer nucleation and advancement on crystal surfaces through monomer addition; and nonclassical pathways, termed crystallization by particle attachment (CPA), involving the formation of metastable precursors that play a direct role in crystallization. To examine these processes at near molecular resolution, my group has developed advanced atomic force microscopy (AFM) techniques to elucidate CPA processes in situ under solvothermal conditions. This unique AFM system is capable of capturing time-resolved dynamics of particle addition and post-attachment rearrangement, thus opening new pathways to probe crystal growth under realistic synthesis conditions. We also design â??modifiersâ? to control crystal properties, such as size and morphology. Modifiers are molecules or macromolecules that interact with specific surfaces of crystals and regulate anisotropic growth rates. In this talk, I will describe how we use growth modifiers to control crystallization in two research areas: (1) the development of therapeutic drugs for crystals implicated in pathological diseases, such as kidney stones (calcium oxalate monohydrate) and malaria (hematin); and (2) the rational design of microporous zeolites with improved physicochemical properties for applications in catalysis, adsorption, and ion-exchange. Broad challenges associated with tailoring material properties will be discussed, along with the unique ways we investigate mechanisms of crystal growth and modification.