Controlling the microdomain orientation in block copolymer thin films via cross-linkable random copolymer neutral layer

Various cross-linkable poly(styrene-random-methyl methacrylate) (P(S-r-MMA)) that can neutralize substrates are reviewed. Four efficient cross-linkable random copolymers incorporated with benzocyclobutene (BCB), glycidyl methacrylate (GMA), azide and ketene functional groups can be used to prepare a thin, cross-linked neutral layer. On this cross-linked layer, polystyrene-block-poly(methyl methacrylate) (P(S-b-MMA)), thin films produce microdomains oriented perpendicular to the substrate, confirming the effective neutralization of the substrate to both PS and PMMA blocks.