Contents: (Small 3/2014)

Block copolymer (BCP) thin fi lms self-assemble to form nanoscale patterns, as K. K. Berggren and co-workers report on page 493. On a smooth substrate, the polystyrene-block-poly(dimethylsiloxane) copolymer forms randomly oriented inplane cylinders with a 35-nm period (images on the left). A set of sacrifi cal nanoposts made of poly(methyl methacrylate) directed the self-assembly to form (center top to bottom): square arrays of spheres or holes, and square and hexagonal meshes with bimodal hole-size distributions. The posts and the polystyrene are removed by etching and the fi nal pattern consists of oxidized poly(dimethylsiloxane)