Controlling CaCO3 nucleation with halogen-terminated self-assembled monolayers

Abstract

Although understanding and controlling CaCO3 nucleation is crucial for both biological and artificial mineralization, there are some fundamental issues, including the impact of surface free energy on CaCO3 nucleation remains unclear. Furthermore, as the abundant elements in nature, halogens can incorporate into organic matrices and participate in the nucleation process. However, their specific influences on CaCO3 nucleation are poorly understood. Here, we investigate how halogen chemistry surfaces control CaCO3 nucleation through constructing halogen (F3, Cl, Br, I)-terminated self-assembled monolayers as model surfaces and measuring the nucleation kinetic/thermodynamic parameters of CaCO3 on them for the first time. The results demonstrate that the abilities of halogen chemistry surfaces to promote CaCO3 nucleation are determined by either thermodynamic or kinetic control, depending on the supersaturation range. Under thermodynamic control, the CaCO3 nucleation efficiency on various halogen chemistry surfaces decreases in the order of F3, Cl, Br and I, which is consistent with the increasing order of surface free energy. Our work sheds new lights on the correlation between materials’ abilities to control CaCO3 nucleation and their surface free energies, and provides a simple strategy for controlling CaCO3 nucleation.