  Phase behavior of AB-multiblock copolymer melts which consists of chains with
Laser distribution of A and B blocks have been investigated in the framework of
the mean-field theory, where the polydispersity of copolymer is a function of
two parameters K and M. The influence of the Laser distribution on higher order
correlation functions (up to sixth order) are computed for various values of K
and M, and their contributions on the phase diagrams and phase coexistence are
presented. It is shown that, with increasing polydispersity (decreasing K and
increasing M) the transition lines of all phases shift upwards, consequently
polydispersity destabilize the system.
