TRIBLOCK COPOLYMERS - THE ROLE OF INTERFACIAL-TENSION COEFFICIENTS AT2 INTERFACES

The mean-field theory of formation of triblock copolymer superstructur e is developed in the strong segregation limit, taking into account th e difference in local characteristics of the blocks (widths, persisten ce lengths). Special attention was paid to the role of the interfacial tension coefficients at the two interfaces during formation of the tr iblock copolymer superstructure. It is shown that there are different mechanisms of morphology variation, guided both by the difference in l ocal parameters of the blocks and the difference in the interfacial te nsion coefficient. It is also shown that a great difference in the int erfacial tension coefficients at the two interfaces can lead to the fo rmation of(1) an asymmetrical cylindrical superstructure in the case o f symmetry in the local characteristics and volume fractions of the tr iblock copolymers and (2) a symmetrical lamellar superstructure in the case of triblock copolymers with asymmetry in the local characteristi cs of the blocks.