Polyelectrolyte multilayer nanoreactors toward the synthesis of diverse nanostructured materials

The preparation of nanostructured materials with defined composition and shape is of immense scientific and technological interest. Polyelectrolyte multilayers are promising nanoreactors which have been applied for a broad range of nanomaterials synthesis, because the multilayer films can be tuned with desired composition and thickness, can be deposited onto different substrates with predetermined morphologies, and can be easily removed after nanomaterials synthesis. This review reports the recent advances on the synthesis and characterization of a variety of nanostructured materials generated by using polyelectrolyte, multilayers assembled onto both planar and colloidal substrates as nanoreactors. By loading small molecular precursors (including metal ions, metal complexes, metal alkoxides, and polymer monomers) into such polyelectrolyte multilayers, followed by chemical or physical treatment, thin hybrid nanoparticulate films, core-shell colloids and hollow spheres can be prepared in a controlled manner. Polyelectrolyte multilayer-coated colloidal assemblies (colloid arrays or colloidal crystals) can also be used to prepare 2-dimensional surface arrays and 3-dimensional macroporous materials with tunable morphologies and compositions. The potential applications of these nanomaterials are briefly discussed. (C) 2004 Elsevier Ltd. All rights reserved.