Multiblock copolymers at interfaces

Summary We consider the configurations and the various regimes when an alternating, symmetric, multiblock copolymer made of successive sequences of A and B monomers with equal lengthZ is at the interface between two immiscible solvents that are respectively good for one of the sequences and poor for the other one. We find two semi-dilute regimes, when the copolymers overlap. For monomer concentrations belowГ ^**, we find a first range where the thickness of the copolymers is constant and equal to the radius of a sequence. For concentrations larger thanГ ^**, a second regime appears, where the seqeunces stretch our and adopt a conformation similar to what was reported for grafted polymers. Finally at a concentrationГ _sat, the interface is completely saturated, and the copolymers form micelles in the bulk: it becomes energetically more favourable to have copolymers in the bulk than at interface. Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4‘8, 1994.