Unique crystal morphology of hydrophobic CaCO 3 composite by sodium trisilanolate in a mixture of a water-miscible organic solvent and water

Abstract

We describe unique crystal morphologies of hydrophobic CaCO 3 crystals in a mixture of water and tetrahydrofuran (THF). After addition of sodium trisilanolate [(c–C 5H 9) 7Si 7O 9(ONa) 3] ( 1 ̄ ) into the mixture of water and THF, calcium reactants (0.1 M CaCl 2 and 0.1 M (NH 4) 2CO 3) were added to the reaction mixture at 30°C. FT-IR and SEM images showed that concave terraced calcite was obtained in 80% THF solution. In the absence of 1 ̄ , the crystalline product was a mixture of rhombohedral calcite with aggregated vaterite particles. The hydrophobic modified surface of the concave terraced calcite was confirmed by the contact angle and dispersability in organic solvents.