Self-assembling of ABC linear triblock copolymers in nanocylindrical tubes.

By employing Monte Carlo simulations for various tube diameters and preferences of the tube surface for the A, B, and C segments, the morphologies of A(5)B(5)C(5), A(5)B(10)C(5), and A(5)B(5)C(10) triblock copolymer melts confined in nanocylindrical tubes were examined. The interaction parameters between different segments were considered constant epsilon(AB)=epsilon(AC)=epsilon(BC)=0.3k(B)T, the tube diameter was changed from d=9xlattice parameter to d=33xlattice parameter, and the preferences of the tube surface for the segments A, B, and C (-epsilon(AS),-epsilon(BS), and -epsilon(CS)) were varied between 0.05k(B)T and k(B)T. ABCCBA alternately stacked disks were generated in most tubes when the preference of the tube surface for any of the segments was weak, and the morphologies tended to transform into curved lamellae in tubes with large diameters when the preference for one of the segments was high. Numerous novel morphologies, such as ABC double helixes, AB single helix+C double helixes, AB double helixes+C quadruple helixes, plate morphologies with fins, dendrites, etc., which were located in the phase diagram between the stacked disks and the curved lamellar structures, were identified. Additionally, the orientation parameters indicating the alignments of the polymer chains were calculated and correlated with the morphologies.