Surface-modifying layers, including neutral layers for vertical domain-forming block copolymers of styrene and methyl methacrylate are provided. Also provided are self-assembled block copolymer structures incorporating the surface modifying layers, methods of fabricating such structures and methods of using the structures in BCP lithography applications. The surface-modifying layers comprise a crosslinked copolymer film, wherein the crosslinked copolymers are random copolymers polymerized from styrene monomers and/or (meth)acrylate monomers and crosslinkable epoxy group-functionalized monomers. The crosslinked copolymer films are characterized by a high content of the crosslinkable epoxy group-functionalized monomer.