ORDERING OF DIBLOCK PS-PBMA THIN-FILMS - AN X-RAY REFLECTIVITY STUDY

X-ray specular reflectivity studies of symmetric PS/PBMA (polystyrene/ polybutylmethacrylate) diblock copolymer thin-films deposited on silic on substrates are presented. Films of different thickness in the disor dered state are annealed for times ranging from a few seconds to sever al hours. The annealing process produces a lamellar ordering throughou t the film which in turn, leads to the formation of holes or islands a t the surface of the film. By measuring the specular reflectivity of s uch films, it is possible to access the bottom (from the interface sil icon-thin film to the lowest part of the film) and the top (from the i nterface silicon-thin film to the highest part of the film) thickness of the films. These two thicknesses which are very accurately measured give us information about the kinetics of ordering and the results ar e analyzed in terms of spinodal decomposition versus nucleation of the domains. (C) 1998 Elsevier Science B.V. All rights reserved.