Templated self-assembly of block copolymers - Toward the rational design of plasmonic nanorods

Shape-defining hard templates containing arrays of aligned cylindrical nanopores have been exploited as a powerful tool in the synthesis of tubular and solid, rod-like one-dimensional (1D) nanostructures consisting of inorganic and polymeric materials. Gaining control over the mesoscopic fine structure in the 1D nanostructures thus obtained has remained challenging. However, it is easy to conceive that their properties largely depend on internal features characterized by mesoscopic length scales. The self-assembly of block copolymers inside nanopores with hard confining pore walls can be exploited to rationally generate 1D nanostructures with internal self-assembled mesoscopic fine structures. These self-assembled mesoscopic fine structures can be converted to mesopores, into which functional inorganic materials can be deposited. Thus, 1D nanostructures that contain replicas of helical mesopores consisting of functional inorganic materials could be obtained. The complex shapes of the inorganic entities might add additional functionalities to those associated with the bulk inorganic material and with the anisotropy of plain 1D nanostructures. In this way, helical structure motifs can be generated that may exhibit specific optical properties, such as circular dichroism, as shown by simulations.