CONFINEMENT OF BLOCK-COPOLYMERS ON PATTERNED SURFACES

Smectic ordered films of the copolymer PS-P2VP were studied on periodi c silicon surfaces (surface gratings). The modulation of the film surf ace with respect to that of the underlying substrate was found to be e ither in phase (conformal) or-surprisingly-out of phase (anticonformal ). The critical height of the surface grating which is defined by the transition from conformal behavior to the anticonformal conformation o f the films was found to be proportional to the lamellar height of the diblock copolymers. This has been quantitatively understood within a mean field theory as a result of balancing the deformation and interfa cial energies. Furthermore, diblock copolymer films propagate the subs trate roughness by significantly larger distances than observed for am orphous homopolymers.