ORDERED DIBLOCK COPOLYMER FILMS ON RANDOM COPOLYMER BRUSHES

Optical microscopy, neutron reflectivity, and small angle neutron scat tering studies were used to investigate the structure of thin films of symmetric diblock copolymers of P(dS-b-MMA) as the interactions betwe en the copolymer and the substrate were changed in a systematic manner . In cases where there was a strong preferential segregation of one of the components to the substrate, the lamellar microdomains were orien ted parallel to the film surface. However, on a nearly neutral substra te, a mixed morphology was found where the lamellae adjacent to the fr ee surface are oriented parallel to the plane of the film, while the l amellae adjacent to the substrate are oriented normal to the plane of the film.