| Abstract
| - The formation mechanisms of complex BaSO4 fiber bundles and cones in the presence of polyacrylate sodium saltvia a bioinspired approach at ambient temperature in an aqueous environment are reported. These complex organic−inorganic hybrid structures assemble after heterogeneous nucleation of amorphous precursor particle aggregates onpolar surfaces, and the crystallization area can be patterned. In contrast to earlier reports, three different mechanismsbased on the oriented attachment of nanoparticles were revealed for the formation of typical fibrous superstructuresdepending on the supersaturation or on the number of precursor particles. (A) High supersaturation (S> 2): largeamorphous aggregates stick to a polar surface, form fiber bundles after mesoscopic transformation and orientedattachment, and then form a narrow tip through polymer interaction. (B) Low supersaturation (S = 1.02−2): onlya few fibers nucleate heterogeneously from a single nucleation spot, and amorphous particles stick to existing fibers,which results in the formation of a fiber bundle. (C) Vanishing supersaturation (S = 1−1.02): nucleation of a fiberbundle from a single nucleation spot with self-limiting repetitive growth as a result of the limited amount of buildingmaterial. These growth processes are supported by time-resolved optical microscopy in solution, TEM, SEM, and DLS.
|
