Abstract: Hydrophobic calcium carbonate nanoparticles were prepared via crystallization of calcium carbonate with a surfactant in methanol. The product was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and the contact angle analysis. In the experiments, the surfactant could not only control the crystal shape but also modify the surface of calcium carbonate. The ellipselike nanoCaCO 3 particles with an average diameter of 40 nm have been obtained under given experim ental conditions. The crystal polymorph of the final particles was aragonite and calcite. From FTIR spectra, we could conclude that the surfactant has been bound to calcium carbonate. The contact angle analysis indicates that the final calcium carbonate is hydrophobic. We have succeeded in surface modification of calcium carbonate in situ.

Key words: calcium carbonate, biomineralization, nanoparticle, surfactant, in situ