Preparation of amphiphilic triblock copolymer brushes for surface patterning

This paper describes the formation of poly(methyl methacrylate)- b -poly(dimethylamino ethylmethacrylate)- b -poly(methyl methacrylate) (PMMA- b - PDAEMA- b -PMMA) and poly(methyl acrylate)- b -poly(methyl methacrylate)- b -poly(hydroxyethyl methacrylate) (PMA- b -PMMA- b -PHEMA) brushes and phase segregation by these materials upon exposure to a poor solvent for the outer block. Synthesis of the brushes employs room-temperature atom-transfer radical polymerization from a surface, and formation of multiblock copolymers simply involves changing the monomer solution that surrounds the substrate. Phase segregation by both types of triblock brushes in the presence of a poor solvent for the outer block results in surface domains that are about 50 nm in diameter. Sizes of domains are more uniform with PMMA- b -PDAEMA- b -PMMA than PMA- b -PMMA- b -PHEMA, but this may be specific to the solvent treatments employed for the two polymers. Formation of nanodomains by triblock copolymers appears to be a widespread phenomenon.