A method comprises forming a first structured pattern having a first line width on a substrate. A polymer brush is deposited on the structured pattern, which is annealed a first time at a first temperature and then annealed a second time at a second temperature higher than the first temperature. A block copolymer is deposited on the structured pattern and polymer brush, and aligned first block and second block structures are formed on the structured pattern and polymer brush. The first block structures and portions of the polymer brush and the structured pattern positioned beneath the first block structures are removed, and the substrate between the second block structures is exposed. The second block structures are then removed to form a second structured pattern in the substrate having a second line width, the second line width being smaller than the first line width.