fig5

Figure 5. Crystalline hierarchical structure process of CaCO₃. (A) Supramolecular interaction between some functional groups of egg white and Ca²⁺; (B) Uniform ACC nanoparticles were formed at the initial stage of the reaction; (C) The aggregation of some nucleation and ordered structures under electrostatic interaction and van der Waals force; (D and E) ACC nuclei begin to aggregate and form mesoscale layered CaCO₃ nanoparticle arrangement; (F) Nanoparticles are constructed, and hierarchical structures are formed by a self-assembly process; (G) The flake CaCO₃ crystals aggregate and self-assemble to form a wool spherical upper structure with many fibers. ACC: Amorphous calcium carbonate.