THEORY OF BLOCK-COPOLYMER INTERFACES IN THE STRONG SEGREGATION LIMIT

An extension of the Helfand theory of equilibrium properties of interfaces between different polymers is presented. The corrections to the interface width due to higher-order terms in gradient expansion of the free energy of the system are shown to be negligible in comparison with ''end'' corrections due to the connectivity of blocks. It is also shown that the latter corrections that are specific for block copolymers are typically much larger than end corrections for a system of immiscible homopolymers. The effect of fluctuations of concentration profiles is also analyzed. It is shown that the effect results in an appreciable increase of the apparent interface width.