Influence of polydispersity on the phase behavior of statistical multiblock copolymers with Schultz-Zimm block molecular weight distributions

In this paper we investigate in a systematic way the influence of polydispe rsity in the block lengths on the phase behavior of AB-multiblock copolymer melts. As model system we take a polydisperse multiblock copolymer for whi ch both the A-blocks and the B-blocks satisfy a Schultz-Zimm distribution. In the limit of low polydispersity the expressions for the vertex functions are clarified bg using simple physical arguments. For various values of th e polydispersity. the pn;se diagram is presented, which shows that the regi on of stability of the bce phase increases considerably with increasing pol ydispersity. The strong dependence of the periodicity of the microstructure on the polydispersity and on the interaction strength is presented.