We developed a novel route to control both mineralization and polymerization inside a nanoreactor based on a miniemulsion system to create organic-inorganic hybrid nanomaterials with diverse structures and morphologies. Nanodroplets of calcium nitrate (Ca(NO 3) 2)/monomer and nanodroplets of sodium carbonate (Na 2CO 3) were separately prepared and suspended in the oil phase. They were mixed through the fusion and fission process triggered by ultrasonication to precipitate a biomineral only inside the nanodroplets. In the presence of monomer, 2-hydroxyethyl methacrylate (HEMA), we could obtain unique structures of nano-sized CaCO 3 particles, which were crystalline with spherical or rod-like shapes or amorphous. By subsequent polymerization, we could encapsulate nano-CaCO 3 inside the polymeric nanoparticles at a desired stage of crystal growth. The preincubation period for CaCO 3 nucleation and growth and the polymerization rate were important factors to manipulate the structures and polymorphs of nano-CaCO 3 inside the hybrid nanoparticles, owing to inhibition of crystal growth and transformation by polymerization of HEMA. Also, the growth of rod-like CaCO 3 inside the nanoparticles led to formation of spheroidal hybrid nanoparticles. By using hybrid nanoparticles as building blocks, we could produce nanofilms containing nano-CaCO 3 with a variety of sizes and structures. Crystal transformation of amorphous CaCO 3 was induced inside the nanofilm by increasing the temperature to above the T g of PHEMA.
ASJC Scopus subject areas
- Materials Chemistry