Chemically amplified molecular resins for shrinkage-controlled direct nanoimprint lithography of functional oxides: an application towards dark-light dual-mode antibacterial surfaces

Abstract

Although the olefin-based polymerizable sol–gel (PSG) approach has brought about significant advancements in the domain of direct and scalable nanoimprinting of oxides, the high feature size shrinkage (>75–80%) due to low metal content remains a challenge. To address this, our study introduces tailor-made bifunctional monomers containing acetoacetyl and epoxy/oxetane moieties, enabling the formulation of imprintable single-source molecular precursor-based resins with tunable metal content. The introduction of epoxy/oxetane functionality serves a multi-purpose, enabling ring-opening polymerization in a chemically amplified manner while offering additional advantages such as oxygen insensitivity, good adhesion and higher metal content by alleviating the requirement of reactive diluents. The proof-of-concept imprinting studies using resins of candidate metals (Ti, Zr and Nb) have shown a reduced feature size shrinkage of the oxides to as low as ∼50%. The functionality of patterned metal oxide nanostructures is exemplified by TiO₂/AgBr nanocomposites—fabricated via two different approaches—displaying high antibacterial efficacy against Escherichia coli under dark-light dual-mode conditions. Our study opens up new avenues in the realms of direct nanoimprinting of functional inorganic materials and their biological applications.