Both positive and negative replicas of copolymer arrays are produced using crosslinked poly(dimethylsiloxane). Negative replicas of the nanoscopic features are manufactued by entrapping air within the microdomains. Positive replicas are produced with similar to1:1 aspect ratios by the PDMS filling the nanoscopic, cylincrical cavities. The Figure shows an AFM image of a negative replica (size: 2 mum x 2 mum, inset: Fourier transform of image).