Amphiphilic Polypeptides as a Bifunctional Template in the Mineralization of Calcium Carbonate at the Air/Water Interface

A well‐defined amphiphilic polypeptide, poly(glutamic acid) 22 ‐ block ‐poly(alanine) 8 (PGlu 22 ‐ b ‐PAla 8 ), which plays the roles of both soluble (functional) additive and insoluble (structural) matrix, is employed to mediate the mineralization of CaCO 3 at the air/water interface. X‐ray diffraction (XRD) and Raman spectroscopy, for example, show that the polymorph of CaCO 3 particles obtained is calcite. The observations from SEM and TEM suggest that PGlu 22 ‐ b ‐PAla 8 initiates the amorphous precursor phase and heterogeneous nucleation of CaCO 3 at the air/water interface, while temporarily stabilizes the gelatinous precursors as a process‐directing agent; nevertheless, the initial concentration of Ca 2+ controls the procedure of crystallization and the final morphology of CaCO 3 particles. Such “bifunctional” amphiphilic‐polypeptide‐regulated mineralization at the air/water interface may be applied to the synthesis of many kinds of symmetrical inorganic/organic hybrids.