Nanoindentation in crystal engineering: Quantifying mechanical properties of molecular crystals

Nanoindentation is a technique for measuring the elastic modulus and hardness of small amounts of materials. This method, which has been used extensively for characterizing metallic and inorganic solids, is now being applied to organic and metal-organic crystals, and has also become relevant to the subject of crystal engineering, which is concerned with the design of molecular solids with desired properties and functions. Through nanoindentation it is possible to correlate molecular-level properties such as crystal packing, interaction characteristics, and the inherent anisotropy with micro/macroscopic events such as desolvation, domain coexistence, layer migration, polymorphism, and solid-state reactivity. Recent developments and exciting opportunities in this area are highlighted in this Minireview. Poking crystals: The application of nanoindentation in crystal engineering provides an important breakthrough in establishing links between microscopic structures and macroscopic properties. This Minireview highlights some of the advantages of this technique for studying the mechanical behavior of organic crystals