Whenever periodic patterning at the nanoscale over a large surface is required, block-copolymers (BCPs) represent an extremely attractive alternative for lithography1 and nano-templating,2 because of the low cost, if compared to conventional photolithography,3 and the high throughput, if compared to serial lithographic processes, such as electron beam lithography (EBL).4 Despite the relatively simple structure of BCPs, two different linear homopolymers linked to each other at one end by a covalent bond, when annealed above the glass transition temperature, they spontaneously microphase separate generating a variety of periodic nanostructures. The periodicity (L0 ) of the microdomains can be varied in the 10 – 100 nm range by properly adjusting the molecular weight and the interaction parameter of the two blocks.5In this work, the combination of BCP lithography and ultra-low energy …