Microphase separation in diblock copolymers with amphiphilic block: Local chemical structure can dictate global morphology

Using dissipative particle dynamics, we study microphase separation in the melt of amphiphilic/nonpolar diblock copolymers in the strong segregation regime. We show that the phase diagram for the copolymers with an amphiphilic block can be significantly different from that known for the conventional diblocks. In the limit of significant amphiphilicity (surface activity), the resulting morphology corresponds to thin channels and slits of amphiphilic units penetrating through the matrix of a majority non-polar component. The physical reason behind this is connected with the surface activity of amphiphilic monomers, which forces them to be located in the regions of maximum concentration gradient. (C) 2008 Elsevier B.V. All rights reserved.