Calcite nucleation on the surface of PNIPAM–PAAc micelles studied by time resolved in situ PXRD

Abstract

Biominerals such as CaCO₃ have been studied extensively in an effort to replicate materials found in nature. But understanding and controlling the formation of CaCO₃ has proved a challenge for example in regards to control over crystallite size. The formation of pure calcite has been studied to some degree and a myriad of materials were made utilizing organic additives to control morphology, polymorphism and crystallite size. In this work, these aspects were combined by applying PNIPAM-b-PAAc micelles as control agents for calcite crystallization. The crystallization mechanism in this system was studied by time resolved in situ PXRD. This revealed that crystalline nanoplatelets of calcite were formed on the surface of the polymer particles. Higher concentration of polymer leads to purely crystalline calcite nanoplatelets with complete inhibition of growth of larger crystallites.