Thickness-dependent Phase Transition Behavior of Block Copolymer Thin Films

Abstract

Understanding on the phase behaviors and transitions of block copolymers (BCPs) such as order-to-disorder and order-to-order transitions is important to design demanded structure of self-assembled arrays. In this study, we investigated the phase transition behavior of BCPs in film geometry on preferential substrate depending on film thickness, then this transition behavior of thin film was compared with bulk system. Phase transition temperatures of BCPs confined in a film geometry are influenced by the interfacial interactions at air/polymer and polymer/substrates and their effects on BCP films were more significant in thinner films. The transition temperatures and morphologies of BCP films were investigated by Grazing Incidence small-angle X-ray scattering (GISAXS) measurements and Transmission Electron Microscopy (TEM).