A Dual Functional Layer for Block Copolymer Self-Assembly and the Growth of Nanopatterned Polymer Brushes

We present a versatile method for fabricating nanopatterned polymer brushes using a cross-linked thin film made from a random copolymer consisting of an inimer (p-(2-bromoisobutyloylmethyl)styrene), styrene, and glycidyl methacrylate (GMA). The amount of inimer was held constant at 20 or 30% while the relative amount of styrene to GMA was varied to induce perpendicular domain orientation in an overlying P(S-b-MMA) block copolymer (BCP) film for lamellar and cylindrical morphologies. A cylinder forming BCP blend with PMMA homopolymer was assembled to create a perpendicular hexagonal array of cylinders, which allowed access to a nanoporous template without the loss of initiator functionality. Surface-initiated ATRP of 2-hydroxyethyl methacrylate was conducted through the pores to generate a dense array of nanopatterned brushes. Alternatively, gold was deposited into the nanopores, and brushes were grown around the dots after removal of the template. This is the first example of combining the chemistry of nonpreferential surfaces with surface-initiated growth of polymer chains.