Figure 1. Host-guest self-assembly of blended BCPs.

The chemical structures of the PDMS-b-PS and PS-b-PFS diblock copolymers (di-BCPs) used for the self-assembly is shown. The schematics of the as-spun and self-assembled morphologies of the blended BCPs are also presented. A mixed solvent vapor of heptane and toluene induces the formation of a perforated lamellar morphology of PDMS-b-PS that can precisely accommodate the spherical morphology of PS-b-PFS because heptane is selectively segregated in the PDMS blocks, whereas toluene swells PS and PFS blocks more preferentially. An inorganic dots-in-holes nanostructure is produced by oxidation of the hierarchically assembled BCP microdomains. Plasma oxidation selectively removes the PS, while oxidizing PDMS and PFS into stable inorganic materials. The array of metallic nanorings can be obtained from pattern-reversal of the dots-in-holes nanostructure.