Preparation of Highly Ordered Silica and Vanadium Oxide Nanoparticles on Surfaces using Diblock Copolymer Micelles as Templates

摘要

Recent developments in nanoparticles and nanostructured materials have opened new opportunities to build up functional nanostructures. Block copolymers offer many opportunities in this area as they can self-assemble into a variety of structures such as micelles, vesicles, and lyotropic phases . These structures can be used as templates for the preparation of nanostructured metals, semiconductors, and ceramics . Block copolymers tend to self-organize in selective solvents, forming aggregates that are structurally analogous to micelles of associated surfactant molecules. Using solutions of spherical block copolymer micelles, it is possible to get ordered layers of micelles on different substrates by means of spin-coating and dip-coating techniques . This bottom up method offers many opportunities to get ordered nanostructured surfaces. After forming micelles in solution, inorganic precursors of the desired nanocrystals can be introduced into the micelle cores directly as metallic ions or indirectly as counterions. As inorganic precursors mostly metal salts are in use, like Tetrachloroaurate , Titaniumhydroxide , and Cadmiumchloride . Another way is to induce a sol-gel process inside the micelle core to form small titania particles . The preparation of these materials proceeds via several steps in which the structure of the block copolymers is transformed into the inorganic structures, like shown in Figure 1.