Pressure-Regulated Confined Crystallization Drives Self-Organization of Bioinspired Mineral Architectures

Nature employs amorphous precursors to construct inorganic biominerals with highly ordered patterns within spatially confined environments. However, bottom-up fabrication of bulk materials with well-organized patterns remains challenging. Here, we report a pressure-regulated strategy to fabricate inorganic monoliths featuring periodic motifs via consolidation of hydrated amorphous calcium carbonate (ACC) gels. The applied pressure governs both structural water retention and the degree of confinement, thereby tailoring crystallization kinetics. Confined crystallization induces shrinkage through coupled dehydration and phase transformation, generating contractile stresses within bulk monoliths. These stresses trigger surface buckling and drive the spontaneous formation of long-range concentric patterns. With increasing pressure, these periodic features further evolve into three-dimensional surface relief structures. Finite element analysis simulates this dynamic morphogenesis and supports a chemo-mechanical coupling mechanism. These findings provide a bottom-up route for constructing monoliths with complex morphologies and offer insights into biomineralization.