Sol-gel nanocoating: An approach to the preparation of structured materials

Nanocoating, the covering of materials with a layer on the nanometer scale, or covering of a nanoscale entity, to form nanocomposites and structured m aterials using the sol-gel process is reviewed. Templates from spherical na noparticles to complex bicontinuous networks are discussed where either the coated material or the structured inorganic hollow frame resulting after r emoval of the template are of interest in fields of application ranging fro m information storage to catalysis. The sol-gel procedure allows coating of templates with complex shapes on the micrometer to nanometer scale, which some commonly used coating procedures cannot achieve. In addition, sol-gel coating techniques can be applied to delicate systems without disruption of their structure or functionality, for example, the coating of biocomplexes or organic aggregates, such as organogelators. Three-dimensional structure s with elaborate pore architectures, such as polymer membranes and gels, ca n also be infiltrated with sol-gel solutions to achieve nanocoatings.