Phase Behavior of Block Copolymer Brushes: Consequence of Grafting Density Control

Block copolymer (BCP) brushes, surface-anchored BCP chains, form nano-scaled structures in similar fashion to self-assemblies in BCP films. Resulting structures can be utilized to control surface properties in various nanotechnologies, thus a comprehensive understanding on the phase behavior is crucial. Previous studies predicting morphologies in BCP brushes were focused on the role of block composition, segregation strength between the blocks, and solvents while the grafting density was fixed at relatively high value. However, the morphologies and properties of polymer brushes are strongly governed by the grafting density; hence, we aim to understand how grafting density affects the self-assembly in BCP brushes. Using a coarse-grained simulation model of polymer brush, we investigate the self-assembly of BCP brushes with the variation of system conditions to complete a phase diagram which encompasses a wide range of parameter space. We also compare our simulation results with experimental data where grafting density is effectively controlled using a new synthetic method.