POLYMER CONTROLLED CRYSTALLIZATION: SHAPE AND SIZE CONTROL OF ADVANCED INORGANIC NANOSTRUCTURED MATERIALS-1D, 2D NANOCRYSTALS AND MORE COMPLEX SUPERSTRUCTURES

摘要

Recently, exploration of mild environmentally friendly strategies for controlled fabrication of advanced inorganic materials with controlled shape, size, dimensionality, and structure has been heightened. Shape control and exploration of novel methods for self-assembling or surface-assembling molecules or colloids to generate materials with controlled morphologies and unique properties are among the hottest research subjects. In this chapter, the latest advances in the polymer-controlled crystallization of various technically important inorganic crystals are summarized. The so-called double-hydrophilic block copolymers (DHBCs), which contain both a binding block and a solvating block for inorganic surfaces, are demonstrated to exert significant influence on the crystallization and morphology of various inorganic crystals such as BaCrO_4, CaCO_3, BaCO_3, CdWO_4, BaSO_4, ZnO, CdS under near natural conditions. Cone-like bundles of BaCrO_4 nanofibers with diameter 10-20 nm and lengths up to 150 μm can be easily produced at room temperature in the presence of a phosphonated copolymer. A self-limited growth mechanism was proposed for the explanation of the high similarity of the BaCrO_4 nanofiber bundles. A controlled growth of CaCO_3, and BaCO_3 crystals with different sizes and surface strucutures was also addressed. In addition, a fine tuning of crystal morphology and crystal superstructures of 1D and 2D very thin CdWO_4 nanorods/nanobelts, and elongated nanosheets can be realized by a very simple aqueous route in the presence of block copolymers. The results demonstrate that the integration of using DHBCs with taking advantages over the experimental conditions, such as the crystallization sites, temperature, pH value, reactant concentration, will provide very promising routes for controlling the shape, sizes, and microstructure of the hierachical inorganic crystals from nanoscale to macroscopic scale via a simple mineralization process. The materials with controllable shape, size, structure, and dimensionality are expected to find potential applications in the field of advanced materials.