Highly Ordered Nanoporous Template from Triblock Copolymer

Silica nanoporous templates from poly(1,4-isoprene)-block-polystyrene-block-poly(2-vinyl pyridine) (IS2VP) were prepared. The films of IS2VP spin-coated from toluene showed a dimple-type structure with short-range lateral order. When the films were exposed to a mixed solvent vapor of toluene/hexane, a highly ordered and oriented core-shell structure, consisting of an outer shell of PI, a middle shell of PS, and a core of P2VP, was obtained. The PI was degraded by UV-ozone treatment and removed. A film of polydimethylsiloxane (PDMS) was spin coated onto the remaining film with dimple-type structures and, upon heating, was drawn into the interstitial regions by capillary action. Exposure to oxygen plasma converted the PDMS into silica and degraded all other remaining polymers. This led to highly ordered and oriented nanoporous silica that could be used as an etching mask for transfer of the pattern or templates for metal loading.