Metamaterials from Plasma-Treated Block Copolymer Monolith

This work demonstrates a facile method for fabricating thin-film metamaterials with high transmittance and superior impact resistance directly from plasma-treated polystyrene-<i>block</i>-polydimethylsiloxane (PS-<i>b</i>-PDMS) monoliths. Upon oxygen plasma treatment, the cocontinuous PDMS within the PS matrix is oxidized to SiO₂, whereas the PS matrix simultaneously decomposes, yielding a nanoporous SiO₂ thin film with a well-ordered network texture. The resulting monolith exhibits an ultralow refractive index and excellent optical transmittance, thereby functioning effectively as an optical metamaterial. Concurrently, its deliberate nanonetwork architecture affords exceptional impact resistance, highlighting its characteristics as a mechanical metamaterial. As a proof of concept, the SiO₂ nanonetwork is applied as a protective overlayer for indium tin oxide (ITO) conductive lines, demonstrating its potential as a ductile glass coating for fragile conductive components in semiconductor devices.