Lateral versus perpendicular segregation in mixed polymer brushes.
Grafting of incompatible polymers on a substrate prevents macrophase separation and the chains self-assemble laterally. Mixed brushes are exposed to different solvents and the morphology is observed via atomic force and x-ray photoemission microscopy. In a nonselective solvent the different species segregate into parallel cylinders ("ripple structure"). Upon exposure to a selective solvent, we encounter a transition to a "dimple" structure, in which the unfavored component forms clusters. Simultaneously, we observe an enhanced perpendicular segregation. The experimental observations are compared to self-consistent field calculations, where qualitative agreement is found.
Minko
S
S
Institut für Polymerforschung Dresden e.V., Postfach 12 04 11, D-01005 Dresden, Germany.
Müller
M
M
Usov
D
D
Scholl
A
A
Froeck
C
C
Stamm
M
M