抄録
Nanohybrids consisting of one or more nanocrystalline ceramic phases in an appropriate polymer matrix represent a new class of potentially important functional materials for a number of applications. While most of the existing synthesis routes for such nanohybrids lead to a lack in both the crystallinity of the ceramic nanophases and uniformity in the inorganic-organic nanostructures, we have successfully devised a new, novel templating synthesis route, where block copolymers are employed as the building blocks. In the di/tri-block copolymer templating, the hydrophilic and hydrophobic structural segments of the block copolymers are effectively used as the building blocks for inorganic and organic structural units in the resultant nanohybrids. By controlling the processing parameters involved in block copolymer templating, several uniquely ordered structures have been successfully realized, where the nanocrystalline oxide particles of 3 to 5 nm in sizes can be assembled in the hexagonal, cubical and lamellar hierarchical structures. To remarkably enhance the nanocrystallinity of ceramic phases, such as TiO2, in the hierarchical structures, post-treatments with water vapor at relatively low temperatures have been devised, where the flexible Ti-O-Ti bonds were rearranged leading to the much enhanced crystallization for the TiO2 nanoparticles. These nanohybrids demonstrate much enhanced linear and nonlinear optical responses, as a result of the enhancement in nanocrystallinity of the ceramic phase and the well controlled nanostructural configurations.
