Polymer-Controlled Morphosynthesis and Mineralization of Metal Carbonate Superstructures

Abstract

Different morphosynthesis strategies for various metal carbonate minerals such as CaCO₃, BaCO₃, CdCO₃, MnCO₃, and PbCO₃ using double hydrophilic block copolymers (DHBCs) as crystal modifiers are presented. The influence of the DHBCs with different functionalities such as carboxyl, partially phosphonated, and phosphorylated groups on the crystallization and structure formation was investigated. Well-defined crystals with size range from mesoscale to microscale can be easily obtained. More complex higher-order superstructures such as hollow spheres and big spherules with controlled surface structures can also be assembled conveniently. The results show that polymer-controlled mineralization is a versatile tool toward crystal morphogenesis. A time-dependent self-assembly and growth of "sphere-to-rod-to-dumbbell-to-sphere" structures was observed in the case of BaCO₃ under the control of DHBCs, adding to the already reported examples of CaCO₃ and fluoroapatite. In addition, we found that the influence of the DHBCs while increasing the ionic strength was lost in case of CaCO₃, implying that the strong selective interaction between the functional groups of DHBCs and crystals has electrostatic contributions.