Copolymer brushes

Abstract

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 χAB, we found two different regimes. If χAB≳0 a demixing transition occurs when the solvent is poor. An exclusion zone appears close to the grafting surface from where one type of monomers is expelled. In this region a steplike brush is formed by the other monomers. At the extremity of this brush appears then a conventional parabolic brush formed by the excluded monomers. If χAB<0 the monomers are miscible and backwards twisted configurations become very important as |χAB| increases. For larger values of |χAB| the collapse of the system may occur.