Coaxial hetero-nanostructures with controllable shell thickness: a "Pore Widening" method

This report presents a versatile "Pore Widening" method that can readily lead to arrays of multi-layered one dimensional (1D) hetero-nanostructures. Using this simple and facile method, we demonstrate that the thickness of the shell component is controllable by the degree of "Pore Widening". With careful selection of materials and sequences of deposition steps, a variety of polymer-metal, metal-metal and polymermetal-metal core-shell nanowires, as well as metal oxide nanotubes and metal oxide-metal double walled nanotubes can be successfully achieved. This opens up a possibility to tailor new properties of 1D hetero-nanostructures through the judicious combination of different core and shell components in the nanometer size regime.