Theory on phase behavior of triblocklike supramolecules formed from reversibly associating end-functionalized polymer blends

The phase behavior of blends of mono-end-functionalized polymers (denoted by A) and a di-end-functionalized polymer (denoted by B), capable of forming triblocklike supramolecules, is theoretically predicted by using a weak-segregation theory based on the Landau formalism. In this model system, polymers can form diblocklike or triblocklike clusters via associations between end-functionalized groups of A- and B-homopolymers. The free energies of various ordered structures including complex phases such as gyroid and double diamond are calculated within the second-harmonic approximation and the possibility of phase coexistences is examined. It is found that the blends of these functionalized polymers exhibit various phase behaviors including closed loop phase boundary of biphasic coexistence. We also discuss about the stability of cylindrical phase arranged with square symmetry competed with hexagonally arranged cylindrical phase by using a multiple harmonics approach up to the third harmonics.