Crystal Epitaxy and Polymorphism

- Brian K. Olmsted

  It is known that organic molecules often exhibit the tendency to form multiple crystallographically unique packing arrangements from a single compound. The set of unique crystal structures a given compound may form are called polymorphs. The phenomenon of polymorphism is of great interest and importance to several industries attempting to control the production, processing, and development of organic materials in environments in which a particular polymorph is desirable over another. It has been observed that certain organic molecules exhibit specific polymorph selection due to Van der Waals epitaxial direction from some substrates they may be grown on. Such instances of epitaxial polymorph selection are found through extensive iterative processing. By using GRACE (a software package developed by the Ward group to screen for potential conditions of epitaxy) as a tool to help suggest areas of epitaxial scrutiny, a research goal is to develop a high-throughput combinatorial strategy by which new polymorphs may be discovered and the production of desired polymorphs may be controlled.