title: Amphiphilic polypeptides as a bifunctional template in the mineralization of calcium carbonate at the air/water interface.
abstract: A well-defined amphiphilic polypeptide, poly(glutamic acid)22 -block-poly(alanine)8 (PGlu22 -b-PAla8 ), which plays the roles of both soluble (functional) additive and insoluble (structural) matrix, is employed to mediate the mineralization of CaCO3 at the air/water interface. X-ray diffraction (XRD) and Raman spectroscopy, for example, show that the polymorph of CaCO3 particles obtained is calcite. The observations from SEM and TEM suggest that PGlu22 -b-PAla8 initiates the amorphous precursor phase and heterogeneous nucleation of CaCO3 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 CaCO3 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.
authors.affiliation: State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science and Laboratory of Advanced Materials, Fudan University, Shanghai, 200433, P.R. China.
authors.forename: Heng
authors.initials: H
authors.lastname: Cao
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Lin
authors.forename: Jinrong
authors.initials: J
authors.lastname: Yao
authors.forename: Zhengzhong
authors.initials: Z
authors.lastname: Shao
mesh_terms: D000388:Air; D002118:Calcium; D002119:Calcium Carbonate / Q000737:chemistry*; D003460:Crystallization; D004151:Dipeptides / Q000737:chemistry*; D007477:Ions; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013501:Surface-Active Agents / Q000737:chemistry*; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D004151:Dipeptides; D007477:Ions; D008903:Minerals; D010455:Peptides; D013501:Surface-Active Agents; D014867:Water; C004276:glutamylalanine; D002119:Calcium Carbonate; D002118:Calcium