THEORY OF SUPERMOLECULAR STRUCTURES IN POLYDISPERSE BLOCK COPOLYMERS .5. NEW DOUBLE CYLINDRICAL STRUCTURE IN BINARY MIXTURE OF CYLINDER-FORMING DIBLOCK COPOLYMERS

Analytical self-consistent field theory of superstructure formation in a binary mixture of cylinder-forming diblock copolymers in the strong segregation limit is developed. It is shown that for the case when both components of the mixture are 'quasi-isomorphous', i.e. when the domain-forming blocks of the components are different, several types of supermolecular structure are possible depending on the composition of the mixture. The possible types of structure are: mixed cylindrical structure (C), mixed lamellar structure (L), two cylindrical structures (C + C') formed by individual components of the mixture, and, finally, a new double cylinder structure (CC'), formed by cylindrical domains of one component coated by cylindrical layers of another component. Stability ranges of these structures are investigated for different compositions of block copolymers and mixture content.