In this work we use di-block copolymers self-assembling to make templates for the fabrication of well ordered nano-patterned materials. By using Poly (styrene-b-methylmethacrylate) we obtain a close-packed hexagonal configuration of circular pores, with a tuneable length scale of 10–100 nm. Optimal conditions for long-range order of the template are obtained by varying the synthesis parameters. The self-assembled template is then transferred into different substrates to produce different nano-porous materials. We finally discuss the application of this technique to phase change random access memories, showing that, using di-block copolymer templates as etching mask, nano-patterned SiO2 can be used to form ultra dense amorphous bits arrays in crystalline Ge2Sb2Te5 (GST) films.