Spontaneous hierarchical surface engineering of minerals through coupled dissolution‐precipitation chemistry

Abstract

Peculiar hierarchical microstructures in creatures inspire modern material design with distinct functionalities. Creatures can effortlessly construct sophisticated yet long‐range ordered microstructure across bio‐membrane through ion secretion and precipitation. However, microstructure biomimicry in current technology generally requires elaborate, point‐by‐point fabrication. Herein, a spontaneous yet controllable strategy is developed to achieve surface microstructure engineering through a natural surface phenomenon similar to ion secretion‐precipitation, that is, coupled dissolution‐precipitation. A series of hierarchical microstructures on mineral surfaces in fluids with tunable morphology, orientation, dimension, and spatial distribution are achieved by simply controlling initial dissolution and fluid chemistry. In seawater, long‐range ordered film of vertically aligned brucite flakes forms through interfacial dissolution, nucleation, and confinement‐induced orientation of flakes with vertically grown {110} plane, on the edge of which, fusiform aragonite epitaxially precipitates. With negligible initial surface dissolution, prismatic aragonite epitaxially grows on a calcite polyhedron‐packed surface. By tuning fluid chemistry, closely packed calcite polyhedron and loosely packed calcite micro‐pillars are engineered through rapid and retarded precipitation, respectively. Surprisingly, the spontaneously grown microstructures resemble those deliberately created by human or found in nature, and tremendously modulate surface functionality. These findings open new possibilities for facile and customizable engineering of microstructural surfaces, hierarchical heterostructures, and biomimetic materials.