Synthesis of well-defined mixed poly(methyl methacrylate)/polystyrene brushes from an asymmetric difunctional initiator-terminated self-assembled monolayer

Well-defined mixed PMMA/PS brushes were successfully synthesized from an asymmetric difunctional initiator-terminated SAM by combining ATRP and NMRP via a two-step process. In situ dehalogenation was carried out by adding n-Bu3SnH into the reaction mixtures. It was observed that the brush thickness increased with the molecular weight of free" polymers collected from the solutions in nearly linear fashions. It was found that the transitions of water θa on three sets of mixed PMMA/PS brushes with increasing the molecular weight of PS occurred at lower molecular weights after thermal annealing in a vacuum at 120°C for 16 h than those after treatments with CHCl3."