CAREER: Towards Fundamental Understanding and Rational Control of Crystal Growth

University Of Kentucky Research Foundation, Lexington KY

Investigators

Abstract

The project focuses on understanding the role played by solvents and additives in affecting growth morphology and polymorphism of organic crystals with density functional theory (DFT) based concepts and Pearson's HSAB (hard and soft acids and bases) Principle. Solvent molecules should match crystal surfaces of a particular polymorph or morphology with respect to their electronic properties. As the sea of electrons on various faces of a crystal couples with or responds to electronic perturbations due to contact of a solvent/additive, the difference in responding sensitivities of the faces may be described by DFT-based softness and hardness. Applying these concepts to establish HSAB type matching principles between solvents/additives and crystals, we will create a new paradigm to clarify the influence of solvents and additives at the electronic level, advancing the rational design of novel crystal materials for chemical, pharmaceutical and biomedical applications. To carry out the research, undergraduate and graduate students will be recruited and trained in crystal engineering and high-performance computation. In addition, middle- and high-school students will be hosted and involved in the cutting-edge research. A variety of polymorphs (i.e., different ways of internal packing by the same molecules) as well as external shape or morphology of organic crystals can be produced in different solvents with and without additives. Therefore, solvent molecules should match crystal surfaces of a particular polymorph or morphology with respect to their electronic properties. To understand the role played by solvents and additives, we plan to carry out high-performance calculations of the electronic structures of model crystals and solvents/additives, and analyze their electronic properties to establish matching principles. Because the control of polymorphs and growth morphology of organic crystals is an essential task in chemical and pharmaceutical engineering and manufacturing, by uncovering fundamental mechanisms of solvent-crystal and additive-crystal interactions and their impact on crystal growth, this study will allow the rational design of novel solvent systems and additives for improving crystal properties and producing novel materials. The research is relevant to areas such as surface science, nanotechnology, biomineralization and computational chemistry, each of which is crucial to advancing materials science and the understanding of crystal growth.