Hierarchical self-assembly in polymeric complexes: towards functional materials.
Combination of self-assembly at different length scales leads to structural hierarchies. It offers rich possibilities to construct nanostructured matter, nanoscale parts, and switching (responsive) properties based on the phase transitions of the self-assembled structures. Complexation of oligomeric amphiphiles to polymers using ionic interactions, coordination, or hydrogen bonding leads to polymeric comb-shaped supramolecules (complexes), which self-assemble at a length scale of a few nm. Self-assembly at an order of magnitude larger length scale is provided by block copolymers, and combination of the latter two concepts leads to structural hierarchies. They provide e.g. templates for mesoporous materials and nano-objects, and allow switching conductivity and switching optical properties. Structural hierarchies are also observed by complexing moderately monodisperse polymeric rods with amphiphiles. Finally, self-assembly at even a larger length scale upon using colloidal particles may be combined to the above structures, as encouraged by recent observations.
Department of Engineering Physics and Mathematics, and Center for New Materials, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, Espoo, Finland. Olli.Ikkala@hut.fi
Olli
O
Ikkala
Gerrit
G
ten Brinke