Al 2 O 3 Ring Array by Infiltration Synthesis in Polystyrene Antidot Template

The combination of block copolymer (BCP) self‐assembly and a controllable molecular growth process as sequential infiltration synthesis (SIS) is a promising nanofabrication strategy for templating material. The self‐assembly of BCP thin films leads to dense, ordered, organic nanostructures that can be exploited as surface modification layers or as masks for pattern transfer. SIS of inorganic materials into these nanostructured organic templates can originate organic/inorganic hybrids thanks to the selective binding of the metal precursor in the reactive component of the polymeric chains. Upon removal of the polymeric scaffold, the resulting inorganic morphologies mimic those of the self‐assembled BCPs. SIS of TMA and H 2 O precursors in self‐assembled PS‐ b ‐PMMA BCP is the reference system. To expand the library of morphologies pertinent to the BCP phase separation, in this work, a modification of the polymeric template is exploited. SIS is applied on thin films of out of plane cylinder forming PS‐ b ‐PMMA. Prior to SIS, the reactive PMMA component is partially or completely removed, originating in a PS antidot array. The O 2 plasma opening step makes reactive the surface layer of the initially non‐reactive PS antidot array. The hexagonal pattern is still preserved, but the infiltrated nanostructures unfold a peculiar ring‐shaped morphology.