| 초록 |
Nanostructured hollow silica was synthesized by sol-gel reaction of silica precursor using block copolymer templates. We obtained tubules, large hollow spheres, and small hollow spheres with a diameter of tens nanometer, which was controlled by the amount of ethanol in mixed solvents. When the small amount of ethanol was added in solution, tubules, large hollow spheres, and small hollow spheres coexisted. As increasing of the ethanol content, tubules and large hollow spheres gradually decreased and only small hollow spheres were obtained. Counterion species, a mediator between block copolymer templates and silica precursors, determine the morphology of hollow silica. Increment of the ethanol content reduces the dielectric constant of mixed solvents and enhances the stability of ion pairs or degree of counterion binding. Moreover, it induced physically crosslinked block copolymer micelles due to dipole-dipole interaction between protonated corona chains. |
