Abstract
Segregation of eutectic co‐units in eutectoid copolymers is behind of forming lamella‐shaped extended chain‐sequence crystals. These are as cooperative units inhomogeneous microphases (IMP). The mean thickness and the thickness distribution of the IMPs are uniquely related to the lengthdistribution of crystallizable sequences (c‐sequences): The primary elements of the colloid structure in eutectoid copolymers are therefore strictly determined by the chain structure. Clusters are formed comprising a finite number of nearly parallel IMPs alternated with amorphous layers. These clusters are the constitutive elements on the secondary level of the colloid‐structure. Hosemann's linear paracrystal is used for modelling the cluster structure and for describing X‐ray small‐angle pattern.