Copolymer formulation for directed self-assembly, methods of manufacture thereof and articles comprising the same

A pattern forming method comprising:

• providing a substrate;
• disposing upon the substrate a composition comprising:
• a block copolymer comprising a first polymer and a second polymer;
• where the first polymer and the second polymer of the block copolymer are different from each other;
• and
• an additive polymer where the additive polymer comprises a bottlebrush polymer;
• where the bottlebrush polymer comprises a polymeric chain backbone and a grafted polymer that are bonded to each other;
• and where the bottlebrush polymer comprises a polymer that is chemically and structurally the same as one of the polymers in the block copolymer or where the bottlebrush polymer comprises a polymer that has a preferential interaction with one of the blocks of the block copolymers;
• and
• a solvent;
• and
• annealing the composition to facilitate domain separation between the first polymer and the second polymer of the block copolymer to form a morphology of periodic domains formed from the first polymer and the second polymer;
• where a longitudinal axis of the periodic domains are perpendicular to the substrate.