Conditions for the existence of non-centrosymmetric copolymer lamellar systems

The first non-centrosymmetric lamellar systems were reported recently by Stadler et al. They were obtained from ABC triblock and AC diblock copolymers when they arrange in the sequence "ABCCAABCCA...". We give a tentative theoretical explanation for such a superlattice arrangement and obtain predictions for the phase diagram of such systems in terms of the molecular parameters.