Hydrogen Bonding–Assisted Sequential Mineralization of Polymer–Stabilized Ionic Clusters

Biomineralization achieves intricate hybrid nanostructures through the biomolecule-directed organization of ionic clusters. However, the regulation of ionic clusters remains challenging for biomimetic mineralization. Herein, we establish hydrogen bonding–stabilized calcium phosphate (CaP) clusters in ethanol using poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) as polymeric capping agents. Through tunable hydrogen bonding, we obtain PDMAEMA-regulated CaP clusters of diverse metastable states: (i) concentration-dependent reversible aggregation of CaP clusters, which form hybrid networks; (ii) thermally triggered irreversible aggregation of CaP clusters, which render enhanced networks; (iii) H2O-induced coassembly of CaP clusters and PDMAEMA into hybrid nanochains and phase separation, leading to metastable interfaces. By progressively destabilizing hydrogen bonding through the stepwise addition of H2O, competitive capping agents, and mild heating, sequential mineralization is enabled . Such a sequential pathway drives the controlled transformation of CaP clusters within the PDMAEMA matrix, achieving hydroxyapatite nanorods with tunable aspect ratios under mild conditions, providing new avenues for nanomaterial design.