Fabrication of Nanopatterned Poly(ethylene glycol) Brushes by Molecular Transfer Printing from Poly(styrene-block-methyl methacrylate) Films to Generate Arrays of Au Nanoparticles

This article presents a soft lithographic approach using block copolymer (BCP) films to fabricate functional chemically patterned polymer brushes on the nanoscale. Hydroxyl-terminated poly­(ethylene glycol) (PEG-OH) was transfer printed from the poly­(methyl methacrylate) (PMMA) domains of self-assembled poly­(styrene-block-methyl methacrylate) films to a substrate in conformal contact with the film to generate patterned PEG brushes mirroring the pattern of BCP domains. A key point in the study is that the chemistry of the functional transferred brushes is different from the chemistry of either block of the copolymer; PEG-OH is miscible only in the PMMA block and therefore transferred only from PMMA domains. The functionality of the PEG brushes was demonstrated by the selective immobilization of citrate-stabilized Au NPs (15 nm) and validated the generation of high-quality chemical patterns with sub-30-nm feature sizes.