Block copolymer thin films: pattern formation and phase behavior

During the last decade, research on thin, sub-micron thick, block copolymer films was devoted toward understanding and controlling microstructural. an d topographical features at temperatures T < T-ODT, where T-ODT is the orde r-disorder transition temperature below which thermodynamic interactions fa vor the formation of ordered (phase separated) microstructures. Symmetric d iblock copolymers, the subject, of this review, undergo an isotropic to lam ellar transition when T < T-ODT. Topographical features, 'islands' or 'hole s,' of these films typically reflect the underlying phase separation; and t he dimension of these features, normal to the substrate, is equal to the in terlamellar spacing, L. Two aspects of block copolymer thin films that have not received much attention are discussed in this paper: (1) pattern forma tion in symmetric block copolymers under conditions of T > T-ODT; and (2) p hase behavior of thin film symmetric diblock copolymer/homopolymer mixtures , when T < T-ODT. (C) 2001 Elsevier Science B.V. All rights reserved.