Designed nanostructures createdviaphysicochemical switching of the growth mode between single crystals and mesocrystals

Abstract

Hierarchical architectures consisting of iso-oriented fluorapatite microrods and nanograins are constructed via temporal control of the crystal growth mode by switching a physicochemical parameter.

Demonstrated gradual evolution of disorder in crystalline structures between single crystal and polycrystal via chemical and physicochemical approaches

“…This suggests that the mechanism for the vertical miniaturization is different from that for the lateral miniaturization due to the molecular inclusion in the lattice. As reported in our previous article, 22 the ion concentration at the growth front is maintained for a certain period because the diffusion layer is not formed due to stirring. Smaller crystal grains of ∼10 nm are formed through vertical miniaturization of the growth units by stepwise nucleation at a relatively high degree of supersaturation.…”

“…The structures of FA crystals that are influenced by the addition of acetic acid (chemical approach) and by disturbance of the solution (physicochemical approach) are clearly characterized by selected-area electron diffraction (SAED). Since miniaturization of FA microrods was observed with the addition of D-aspartic acid, which has two carboxy groups, 19,22 the functional group is suggested to modulate the crystal growth through specific adsorption. Thus, we used acetic acid as a simple molecule having a carboxy group.…”

“…Therefore, the control of the crystallographic regularity in mesocrystals has been required to develop bio-inspired structural materials. In our recent work, 22 we succeeded in reversible switching of the growth mode of fluorapatite (FA) between single-crystalline rods and mesocrystalline grains through disturbance of the solution. The primary crystal size was reversibly tuned by the degree of supersaturation at the growth front.…”