A facile fabrication process for polystyrene nanoring arrays

Polystyrene nanoring arrays with outer diameters ranging from 130 to 230 nm were fabricated using low cost and simple fabrication techniques, including nanosphere lithography, argon plasma treatment, immersion in organic solvents and sonication. These nanorings were developed from polystyrene nanospheres pre-assembled on substrates. Scanning electron microscopy revealed that the argon plasma treatment transformed polystyrene nanospheres into hollow cone-shaped nanostructures. X-ray photoelectron and Raman spectroscopy found that the argon plasma changed the composition of the polystyrene nanospheres by forming graphitic materials. The nanoring formation mechanism was discussed based on the instrument analyses.