Controlled mineralization of barium carbonate mesocrystals in a mixed solvent and at the air/solution interface using a double hydrophilic block copolymer as a crystal modifier

Mineralization and crystallization of barium carbonate mesocrystals with various shapes and complex form using double hydrophilic block copolymers (DHBCs) as crystal growth modifiers in a mixed solvent composed of N,N-dimethylformamide (DMF) and deionized water (DIW) have been systematically investigated. The effects of polymer concentration, solvent, and the volume ratio of a mixed solvent on the controlled crystallization of BaCO3 mesocrystals have been examined. Shuttle-like BaCO3 rods with different sizes and ratios of average length (L) to maximum diameter (D) can be obtained by simply altering polymer concentration in the mixed solvent. In addition, complex hierarchical shuttle-like aggregated structures can be formed at the air/solution interface that were dramatically different from the structure obtained in bulk solution. This crystallization method in a mixed solvent containing a crystal growth modifier represents a simple but versatile route to achieve unique synergic effects on manipulation of the morphology and preferential orientation growth of BaCO3 mineral both in bulk solution and at the air/solution interface, which can be extended for shape control over other minerals or inorganic-organic hybrid materials.