J Phys.Chem.,1996,105, 9362-9370

P. G. Ferreira

Laboratoire de Physico-Chimie Theorique, E.S.P.C.I.. 10 Rue de Vauquelin, 75231 Paris Cedex 05. France

L. Leibler

U.M.R. CNRS-Elf Atochem, C.A.L.. 95 Rue Danton-BP 108, 92303 Levallois-Perret Cedex, France

(Received 17 May 1996; accepted 13 August 1996)

We study a diblock AB copolymer ,brush in good solvent using the self-consistent field approximation. The copolymer chains of the brush are end grafted to a planar surface always by the same type of monomers. Depending on the Flory-Huggins interaction parameter X AB ' we found two different regimes. If XAB>O a demixing transition occurs when the solvent is poor. An exclusion zone appears close to the graf ting surface from where one type of monomers is expelled. ln this region a steplike brush is forrned by the other monomers. At the extremity of this brush appears then a conventional parabolic brush forrned by the excluded monomers. If XAB<O the monomers are miscible and backwards twisted configurations become very important as IXABI increases. For larger values of IXABI the collapse of the system may occur. (1;) 1996 American Institute of Physics. [SOO21-9606(96)51143-8]