Polymer-assisted fabrication of gold nanoring arrays

In this paper, we report a new strategy for the fabrication of gold nanoring arrays via colloidal lithography and polymer-assisted self-assembly of gold nanoparticles (Au NPs). First, multi-segmented polymer nanorod arrays were fabricated via colloidal lithography. They were then used as templates for Au NP adsorption, which resulted in nanoparticles on the poly(4-vinyl pyridine) (P4VP) segments. Continuous gold nanorings were formed after electroless deposition of gold. The diameter, quantity, and spacing of the gold nanorings could be tuned. Three dimensional coaxial gold nanorings with varying diameters could be fabricated on a polymer nanorod by modifying the etch parameters. The nanorings exhibited optical plasmonic resonances at theoretically predicted wavelengths. In addition, the polymer-assisted gold nanorings were released from the substrate to generate a high yield of free-standing nanorings. This simple, versatile method was also used to prepare nanorings from other metals such as palladium.