Self-assembly of A1B1A2(B2) m branched tetrablock copolymer: Length scale and phase transition

Highlights: • In the A₁B₁A₂(B₂)_m tetrablock copolymer, the the length ratio of B₁-block plays a key role in stabilizing the hybrid lamella-sphere (LS_A) phase and corresponding phase transitions. • The periods of L_x and L_y of LS_A phase are modulated by the length of B₁- block in the A₁B₁A₂(B₂)_m tetrablock copolymer. • The symmetry of the phase diagram is broken in the A₁B₁A₂(B₂)_m tetrablock copolymer as the branched number m is increased from 1 to 2, and 3. In this paper, the self-assembly behaviors of branched A₁B₁A₂(B₂)_m (m = 1, 2, 3) tetrablock copolymer with fixed χN = 80 and symmetric composition has been studied using the self-consistent field theory (SCFT), to reveal that the length ratio of B₁-block plays a key role in stabilizing the hybrid lamella-sphere (LS_A) phase as well as corresponding phase transitions. Specifically, we find that not only the stability regime but also the domain spacing of the LS_A can be modulated through tuning the length of B₁-block. So our results will provide helpful guidance for the experimental study on the hybrid nanostructures.