Crystal surface defects as possible origins of cocrystal dissociation

Abstract

In situ atomic force microscopy (AFM) was used to investigate topological crystal surface defects and their possible role in the dissociation of the caffeine–glutaric acid cocrystal at high relative humidity (RH). Topographical scans of the cocrystal suggest that its dissociation is triggered by localized sublimation and involves increased molecular surface diffusion, the formation of line and screw dislocations and the crystallisation of caffeine hydrate.