Systematic Control of Irreversibly Adsorbed Layer in Block Copolymer Thin Films: Self-assembled Copolymer Adsorption Layer

Abstract

Polymer thin films entail a thin adsorbed layer originated from an irreversible adsorption of polymer chains onto solid substrates, which exists even when polymer chains have stronger inter- and intramolecular interactions such as those in block copolymer (BCP) systems. Even though the role of the adsorbed layer can be critical in BCP self-assembly, understanding towards the adsorbed layer remains elusive, and thus its effective control is more challenging. Herein, we introduced a self-assembled copolymer adsorption layer (SCAL) as an effective way to control the adsorbed layer in BCP thin films. The SCAL transferred from the air/water interfacial self-assembly of BCPs is irreversibly adsorbed onto substrates and replaces the natural adsorbed layer when other BCP is additionally coated. We further show that SCAL provides topographic restrictions and enthalpic/entropic preferences to the overlying BCPs, resulting in SCAL-induced self-assembly.