(599e) Preparation of CL-20:HMX(2:1) Nano-Cocrystals Via Spray Drying

Crystal engineering is a rapidly growing area of research of which cocrystals have been of high interest. During cocrystallization, two or more chemical substances are combined in a specific stoichiometric ratio to form a unique crystalline structure with its own unique set of physicochemical properties. The opportunity to tailor properties in this manner has prompted research in a wide range of areas including energetic materials in order to improve properties such as initiation sensitivity and performance. We present the findings of a new route to the synthesis of the recently discovered CL-20:HMX(2:1) cocrystal. Using spray drying, micron-sized amorphous particles are first isolated containing the coformers at the cocrystal stoichiometric ratio. Subsequently, we find that during thermally induced crystallization, the cocrystalline material emerges. Moreover, due to the small particle size of the amorphous precursor, the size of the product crystals is in the highly desired nanoscale regime. These results demonstrate that the amorphous phase can be highly effective at mediating cocrystal formation.