Interface-mediated phase transformation in nanocrystalline particles: The case of the TiO₂ allotropes

Phase transformations are important processes by which materials evolve in both natural and synthetic materials. Understanding the nature, mechanisms, and kinetics of phase transformations, as well as the micro structural changes that accompany them, require comprehensive characterization so as to gain a deeper understanding of atomic scale mechanisms and better control materials properties. A combination of experimental and theoretical techniques has led to improved understanding of how phase transformations are initiated at interfaces and then propagate by growth of the more stable phase at the expense of meta-stable phases. A number of important research studies are highlighted to improve our understanding of this aggregation based phase transformation and control over its mechanism to produce materials with desired properties.