Self-assembled Copolymer Adsorption Layer-induced Block Copolymer Nanostructures in Thin Films

Abstract

Spontaneous adsorption of polymer chains on solid substrates is important as it governs the entire properties of films. Similarly, the adsorption layer exists in the microphase separated block copolymer (BCP) films, playing a critical role in their self-assembly. However, understanding on the adsorption layer in BCP films remains elusive and thus its effective control is more challenging. Herein, we employ a self-assembled copolymer adsorption layer (SCAL), transferred from the self-assembly of BCPs at the air/water interface. The SCAL is irreversibly adsorbed onto substrates and can replace the natural adsorption layer when other BCP is additionally coated. We further show that SCAL guides the thin film nanostructures as it provides topological restrictions and enthalpic/entropic preferences for BCP self-assembly. Thus various novel nanostructures are introduced such as arrays of spacing-controlled hole/micelles, anisotropically clustered micelles and perpendicular nanostructure, etc.