Effective Interface Control of Block Copolymer Thin Films using the Air-Water Interfacial Layer of Short-Chain Block Copolymers

Self-assembly of block copolymer (BCP) thin films is of interest in nanoscience due to their potential to be employed in nanopatterning. For BCP nanopatterning, the vertical orientation of BCP is lithographically useful, which is only realized when the energy of the substrate and interface is neutral for both blocks.

In this study, we propose a strategy to neutralize the interface using the air-water interfacial layer (AWIL) of short-chain BCPs. The short-chain BCPs form a randomly segregated layer at the air/water interface with molecular-level-thick, which can be easily transferred onto any substrates. The BCP thin films on the AWIL-coated substrate have a neutral interface due to the random segregation of AWIL. In addition, the free surface of BCP thin films can be neutralized with AWIL-coated elastomers, enabling a highly aligned sub-10 nm nanopatterning by combining a shearing method.