Pattern treatment compositions comprise a block copolymer and an organic solvent. The block copolymer comprises a first block and a second block. The first block comprises a unit formed from a first monomer comprising an ethylenically unsaturated polymerizable group and a hydrogen acceptor group, wherein the hydrogen acceptor group is a nitrogen-containing group. The second block comprises a unit formed from a second monomer comprising an ethylenically unsaturated polymerizable group and a cyclic aliphatic group. Wherein: (i) the second block comprises a unit formed from a third monomer comprising an ethylenically unsaturated polymerizable group, and the second monomer and the third monomer are different; and/or (ii) the block copolymer comprises a third block comprising a unit formed from a fourth monomer comprising an ethylenically unsaturated polymerizable group, wherein the fourth monomer is different from the first monomer and the second monomer. Also provided are pattern treatment methods using the described compositions. The pattern treatment compositions and methods find particular applicability in the manufacture of semiconductor devices for providing high resolution patterns.